Introduction: Animatronic Tentacle Vine - AKA Cleopatra, the Rare South American Strangler Vine

By The Necro Nomnomnomicon
About: Hands-on DIY lover and borderline crazy crafter. I love Halloween and creepy food.

This Halloween I decided to go with a haunted greenhouse theme and was so excited to see all the creepy plants that were popping up in stores like Target and Fred Meyer. While I was happy with the selection of static plants, I wasn't happy with the moving plants. The ones from Target that bounce up and down and sing "candy candy candy" were especially high on my WTF list.

Since I couldn't find what I wanted, I decided to make what I wanted...a fully moving, creepy looking, very slow and very realistic looking monster plant.

Because so many people have already made versions of Audrey from Little Shop of Horrors, I decided to pull inspiration from one of my favorite childhood shows, the Addams Family...specifically Morticia's plant, Cleopatra...the strangler vine.

As this was my very first animatronic project, I ended up spending far more than I needed just because I kept buying things, using them, and then learning from trial and error what worked and what didn’t. Luckily for you all, I’ll be slimming this list down to only the things you need, hopefully saving you both the time and money I spent getting this all figured out.

Now it’s time for some seriously tough talk. This project is not for the faint of heart. All in all, it took me about two months with one month of initial planning and tons of research and one month for the actual build. True, that included a lot of mistakes and going back to do things twice (or more), but you will still need to calculate in shipping time for supplies, sculpting time, casting time, silicone drying time…you get the picture. Depending on how fast you can move, and how much time you have to devote to this project, I’d still budget at least 3 weeks to a month.

SUPPLIES

Okay, now let’s get onto the good stuff. To try to make this easier for anyone looking to budget this out by sections, I’ve broken the supplies down into what you will need for each component as well as an estimate on the cost. Be aware that these costs are for ordering through Amazon.com and may be found for cheaper at your local hardware store or through other online sources.

Attachments

Supplies

For this project you will need:

TENTACLES

Step 1: ​ASSEMBLING THE TENTACLE STRUCTURE - Drilling the Gears

To start, we’re going to need to assemble the structural ‘insides’ of our tentacles, starting with drilling some holes into our gears in order to wire them up properly.

Organize your gears by descending size.

To make 8 tentacles, I ended up purchasing two sets of the gears (they come in sets of 6 total).

FOR THE LARGEST GEARS: The largest gears are already pre-drilled with a hole through the outer edge. Use this hole as a guide and drill out a hole on the exact opposite side. You can mark these holes using your black Sharpie. You will also want to drill two more holes for a total of five (including the center) following the guide below: As you can see, the hole at the 12 o’clock position is significantly smaller than the rest of the holes. This is going to be our wire guide hole and to help keep the tentacle from twisting too much, we’re going to keep this as close to the diameter of your flex wire as possible. The hole drilled out at the 6 o’clock position will be for your springs, so having this spot slightly larger is fine. The 3 and 9 o’clock position will be used to hold the bottom of your tentacle to your mounting plate so it should be the same diameter as your mounting screws.

FOR THE REST OF THE GEARS: The remaining gears need to get two additional holes, one at the 12 o’clock position for your guidewire and another at the 6 o’clock position for the springs. Be aware that as you go down in gear size, drilling along the edge may be difficult. Watch your fingers! Once all your holes are drilled, it’s time to start assembling your tentacles.

Step 2: ​ASSEMBLING THE TENTACLE STRUCTURE - Building the Internal Structure

Cut a length of your speedometer cable to 8” lengths. You also want to cut a length of Soft Flex wire about 18” long. Attach a crimp bead at one end and pinch to close. Initially, I used the included plastic caps as the endpoint for my tentacles, which is why you will see those in the following photos. Ultimately, I discovered that the tension I placed on the wires was greater than what the caps and hot glue could handle and later replaced them with brass wire stops (sometimes called ferrules) which I crimped into place using my pliers. Pretend this blue cap is actually a brass wire stop.

Before you crimp your wire stop, make sure you also run through one end of your Soft Flex wire, pulling it so that the crimp bead is just outside the top of the wire stop, like the third picture in this series.

Moving on, (and still pretending I’m using the proper wire stops instead of the blue plastic caps) now we want to start adding in lengths of aquarium tubing and black vinyl tubing. The Aquarium tubing is very flexible, and the vinyl tubing is a bit more stiff, so to give the tentacle some strength without sacrificing “wiggle” I used aquarium at the top and black vinyl at the bottom.

I put a small, ¼” length of tubing between the top of the tentacle and the first gear. Then I ‘lock’ it into place with 2-part epoxy. You want to make sure that you lock EVERY PART of this tentacle “spine” down into place. This will help prevent the pieces from moving independently and causing twisting.

When you use your two-part epoxy, make sure you get it in between the tubing and the speedometer cable as well as in the center of your gears and the speedometer cable. You also want to make sure that all your guidewire holes are lined up before the epoxy hardens. Trust me on this.

Continuing on with the gluing and tubing: Then a slightly larger piece, a little over ½” between the first gear and the second gear.

The second and third gear were separated with a length of aquarium tubing about about ¾” inch and the third and fourth gear were also separated by about ¾” but this time using black vinyl tubing for a bit more support and strength.

Continue this pattern down the length of your tentacle, making sure that you never exceed 1” with either color of your tubing.

My first attempt at the tentacles I used a wide variety of sizes all the way up to 2”. I discovered after I’d made all eight that anything over 1” causes wild swinging when you start rigging the tentacles, resulting in twisting that’s really hard to correct. Save yourself the headache and just stick to no length over 1”.

You also want to make sure that you keep at least the bottom two segments separated by the black vinyl tubing as this will help give your tentacle the stiffness it requires to “rise” up when manipulated. If you stick with just the vinyl aquarium tubing, it can be too floppy and you won’t get much movement and your cables will wear out faster.

Speaking of lessons learned with the first three attempts on these tentacles, you are going to want to use the Gorilla Glue 2-part epoxy for gluing your segments together. It’s going to hold everything better than just about anything else I’ve found so far and trust me, once you get this entire thing assembled, the last thing you want to do is have to take it apart to repair an internal tentacle break.

In the 7th photo you can see how each of the guidewire holes is lined up. You can also see the totally useless glue gun I used for the first try at these tentacles. DO NOT USE GLUE GUN GLUE…IT’S NOT STRONG ENOUGH.

The next photo shows a fully completed tentacle. It’s 7 gears high and is an even mix of aquarium tubing and black vinyl tubing.

To really sell the illusion that the tentacles are alive and to give them a bit of curve over the edge of the pot when they’re at rest, we’re going to need to add in some ‘muscle.’ Initially I used elastic cord for this, running it parallel to the Soft Flex cable. You can see the elastic cord on the right side of all these tentacles. This was an “ignorance is bliss” moment as I thought I’d completed all 8 tentacles correctly on my first try! I had no idea how many more times I was going to rip them apart and rebuild them. Learn from my mistakes, young grasshoppers. It will save you time and money.

You can also see in this photo how there were different lengths of tentacles. Yeah, don’t do that. Once we mold the main silicone skin, it won’t matter. Just keep them all about 8” long. The way these are assembled, they move by tugging gently on the beading wire/wire rope.

You can see that movement here in this initial test run I did with my first assembled tentacle in the video above.

While the elastic cord initially worked well, I realized the problem was it quickly lost elasticity and the tentacles started to droop. I also realized at this point the hot glue wasn’t holding and that it was time to try something stronger.

I took the tentacles apart, stripping them all down to a pile of gears, speedometer cable and cut tubing. I then started rebuilding them, one gear at a time, placing a spring in between each segment and making sure to lock it all down using the two-part epoxy.

Step 3: ​SCULPTING THE ‘SKIN’ OF YOUR TENTACLE

Using my extra gears, I made a 9th, ‘static’ tentacle, using my hanger wire instead of the speedometer cable. I also didn’t add any springs as I needed it to be straight up and down.

This tentacle I attached to a piece of wood scrap so I could stand it upright like this: I stuffed the open gaps between the gears with plastic grocery bags to give it a bit of bulk and wrapped the whole thing in blue painter’s tape. And yes, I know what it looks like. Get your minds out of the gutters.

Next I started adding layers of plastilina clay, building up the shape I wanted. I balled up tiny bits of clay and stuck them to the top side of my tentacle, creating texture.

To help smooth the clay and give the tentacle a more organic look, I used my paintbrush dipped in Naptha and went over the entire thing multiple times while sculpting. The Naptha breaks down the clay, helping smooth and soften the edges.

It also works great to erase fingerprints and stray nicks and bumps. Because I wanted it to appear as menacing as possible, I initially sculpted it with jagged teeth. Take it from me…not necessary. Because they were so small, they didn’t mold properly, and I ended up redoing them all anyway.

Speaking of molding, let’s mold this thing!

Step 4: CASTING YOUR TENTACLE

I built a box out of cardboard that I covered in packing tape so the plaster wouldn’t stick to it. I then gave my tentacle a generous coat of Vaseline. Yes, I know I said the clay is oil-based and doesn’t stick to plaster, but I wanted to make doubly sure it released easily.

I followed the directions on my plaster and mixed up enough to reach halfway up my tentacle.

I created the ‘keys’ in my mold by pressing in some rocks just as the plaster was solidifying. This makes it easier to line up and ‘lock’ the two sides of your mold in place when you start actually pouring your skins. Trust me, it really does help make things easier.

Once the first layer of plaster had completely set, I gave it and the still exposed part of the tentacle another coating of Vaseline and then poured the second layer of plaster on top. I let the whole thing cure for 24 hours and then removed the outer cardboard, revealing my finished two-part mold.

I carefully pried it open, pulled out all the clay and voila! A completed tentacle mold ready to fill. Because I knew I wanted to make so many of these bastards, I actually repeated the whole process and made an additional mold.

Okay, no, that’s not true. I made four more for a total of four molds. Unfortunately, not all four survived. I was in a rush and accidentally added too much water to mold number 2 and it never set properly. It ended up so porous that just touching it causes it to crumble.

Mold number 3 ended up basically just turning to mush because the plaster I used was just too old and past its date. Mold number 4 and 5 both worked beautifully, and I ended up rotating between the three surviving molds for the duration of this project.

Let your molds dry 100% before moving onto the next steps. I found leaving them outside in the summer sun for about 5 days was long enough to really make sure they were dry.

You can also speed this process up by popping them into an oven set to 170F/76C for a few hours. When they’re dry, give the interior of your molds a good coat of Vaseline, really working the goo into the surface of the mold and then wiping out any excess. They are now ready to be used!

Step 5: MOLDING YOUR TENTACLE SKINS

Once you have your molds created, it’s time to start actually making tentacles!

Be warned: These steps involve the handling of fairly strong chemicals and should only be done either outside or in an area with proper ventilation. I also suggest you wear nitrile gloves to help keep your hands clean and reduce the possibility of skin contact with what we’ll be mixing up. The tentacles for this project are made from a home-brewed concoction starting with a solid base of tub caulk. If you do not feel comfortable mixing up this mess of mayhem, using pre-made silicone mixtures like those found on Reynold’s website is 100% acceptable.

For anyone who has ever had anything to do with tubes of tub caulk, you know the stuff is thick and gooey. In order to make it flow more and really get into the nooks and crannies of our molds, we’ll need to thin it down a bit. We’ll also need to color it in order to achieve a proper ‘tentacle’ look.

To make your own mad scientist mix of brushable/pourable silicone start by first squirting about 10 good squirts of your clear silicone into a plastic container.

Follow this with about ¼ cup of Naptha.

Add in an equal amount of vegetable glycerine.

Next, add in about 5-6 sprays (about a tablespoon or so) of your lemon oil.

To make the tentacles the right color of green I wanted, I used a mixture of oil paints in sap green and yellow at a ratio of 1:1. Each blob was about the size of a pea.

Using your stir stick, carefully mix this mixture up until it’s all combined. It’ll take a few minutes to work the ingredients together, but once you get it mixed, the resulting goo should be smooth and have a consistency similar to thick cool honey. If you tilt the container, it should slooooooowwwlllyy flow.

Give your prepped molds a quick spray of your saddle soap and then, using a brush, start laying in a layer of your goo. Use your brush to give both sides of your mold a solid coat of your silicone mix, making sure to really get into all the dips and divots. If you find that your mixture is a little too thick, you can smooth it out by dipping your brush into the Naptha and smoothing out your layer.

Make sure you fill the tips of your tentacles in completely as that will be the primary point of contact when we put our two halves of our molds together.

For the rest of the mold, you want to just give it a coat of silicone but not fill the entire thing up solid.

Once both halves of your molds are coated in your goo, put them together and rubber band them in place.

Get another healthy slug of silicone and use it to go over the seams on the inside of your mold where the two pieces meet to help give it some strength. The trick with these steps is to make sure your silicone is thick enough that you don’t end up with tears and thin spots in your tentacle but thin enough that it’s not too heavy for the mechanics we’ll be putting into it later. It’s a bit of trial and error and trust me when I say, you’ll probably end up molding more tentacles than you actually use for this project…but don’t worry, I have plans for those extras that I’ll share with you later…so don’t throw them out!

Set your tentacle molds aside and allow them to cure for at least 6 hours.

Step 6: DE-MOLDING, PATCHING AND TEETH

When it comes time to unmold your tentacles, carefully pry the two sides of your mold apart starting at the end where the top of your tentacle is located. Slowly open your mold and gently loosen any adhesions you might find between the two pieces as a result of extra silicone. Go slowly to help prevent any major ripping. If you do it slowly enough, you should be able to separate the two halves and should end up with a single molded silicone tentacle! Take the time now to inspect your tentacle and see how it looks. YOU ARE GOING TO HAVE RIPS. YOU ARE GOING TO HAVE HOLES. THERE WILL BE SPOTS WHERE THE TENTACLES DIDN’T QUITE STICK TOGETHER RIGHT. THIS ISN’T A PROBLEM. Simply use more of your silicone goo to help seal these imperfections and fix any problems and then hang to cure using your black binder clips to hold the tips. I like using our grapevine to do this step.

You can also use empty soda cans as a way to prop up your tentacles while you touch them up/repair them.

Once you have any holes or imperfections fixed, carefully trim off any flashing that might be leftover. Now let’s add teeth. To do this, all you have to do is suspend your tentacles horizontally and dot the bottom of them with clear silicone straight from the tube.

I found that clipping empty silicone tubes to the railing in our back yard was a perfect way to hold the tentacles in the position I wanted. Dot the bottom of your tentacles with clear silicone and then pull the tip of your caulk tube away slowly as you continue to squeeze out just a tiny bit more silicone. This will result in long, stringy drips. Continue doing this all down both sides of your tentacles to create your teeth.

Allow to cure for about 2 hours or so. Then, when it’s all dry, go through with your scissors and trim off any long strings and cut any spots where the silicone looped back on itself.

You should be left with something that looks like the last photo in this series!

Now just do the above steps 7 more times! Ultimately, you’ll want a total of 8 completed silicone tentacles.

Step 7: BASEBOARD BUILD

Time to move onto the mechanics of this project, starting with the urn. In order to make sure that the mechanical platform we’re building for Cleopatra fits properly, we’ll need to put a lip inside the inner edge of our urn.

Using our self-adhesive door sealer, create a ring just inside the lip of the urn. If you find that the self-adhesive doesn’t stick well to the plastic of the urn, you can supplement it with clear Gorilla glue.

Next, trim down your nylon cutting board so that it fits inside your urn and can rest comfortably on top of the lip you just created using your door sealer. You want to make sure that you also take into account your motor and mark out where it will fit, ensuring that the shaft is in the exact center of your circle.

When cutting out your circle, make sure to put it as close to the edge of your cutting board as possible and hold onto the scrap that results. We’ll be using a bit of that later for another part.

Now you want to mark out where your 8 tentacles will go. I found the easiest way to do this was to use one of my spare gears as my template marker. Drill out all your tentacle holes as well as a hole large enough for your motor to fit into comfortably.

You also want to drill out holes around the edge of your motor hole that corresponds with the screws that hold the two halves of the plastic motor casing in place.

Next, drill out a hole approximately halfway between each of the gear holes you just drilled.

You’ll also want to drill a hole directly behind each of your tentacle spots to help secure the back of your tentacles.

Confused? I can imagine! Okay, here…to make it easier is a map of every hole you need to drill in your cutting board along with what each one corresponds to.

Here, let me break it down, group by group:

Step 8: DRILLING AND THREADING

Following the red diagram, feed the speedometer cable on each of your tentacles through the center holes you drilled in your cutting board and then secure your bottom gear to the board using your screws and nuts.

Following the blue diagram, feed the wire rope through the holes in your cutting board that are closest to the center of your board and let the excess wire hang loose for now.

Following the green diagram you'll want to now secure both sides of your unskinned tentacle to the board by screwing them in place through the bottom gear using one nut and bolt on each side.

Pro Tip: Before we move on, cut speedometer cable is really sharp and hurts if you poke yourself with it. It will also snag clothing really easily. Because a lot of the work we’ll be doing from now on relies on you holding the cutting board (now also called the baseboard) on your lap with the sharp ends pointed down towards your legs, I found the easiest way to keep from really tearing myself up was to use a bit of hot glue to attach a cap of extra aquarium tubing to the end of the cable (third photo in series).

This is also a great picture to show you how the underside of your cutting board should now look with your speedometer cable installed, your bottom gear secured on both sides using nuts and bolts and the wire rope running through the hole for movement.

Step 9: GETTING THINGS IN PLACE

To make our tentacles wave, we’ll have to turn the radial energy generated by our turning motor shaft into linear energy. To do this, we’ll need to first install our motor to our baseboard.

To secure your motor to your board, carefully pry apart the two halves of the plastic housing over your motor and then, using them like a clamshell with one half on one side of your cutting board and the other half on the other, secure your motor in place using screws through the plastic housing the motor came from.

Drill a hole through the center of your urn through the bottom and run your motor cable through that hole. Carefully drop your cutting board into place on top of the door sealer lip you made earlier. You should now have all your tentacle mechanics and your motor secured to your cutting board and have something that looks like the second photo in this series.

Now we'll need a way to attach our tentacles to the center shaft.

Step 10: TRANSFORMING RADIAL MOVEMENT TO LINEAR MOVEMENT

Cut out a circle of nylon cutting board from your scrap approximately 2” across.

Cut a second hole in the center of the nylon circle that is the exact size of your ball bearing and press into place.

Carefully screw 8 of your eye pins into the outside of your nylon circle equidistance apart and clip one swivel clip to each of the 8 eye pins.

Attach the entire thing to the shaft of your motor using the bolt that came with the motor itself. You should end up with something that looks like the second photo in this series.

Gently feed the end of one of your wire ropes through the side holes of one of your stop swivels, loop the rope through the eye of your swivel clip and then feed it back through the same side hole of your stop swivel.

Tighten down your stop swivel just to the point where it holds the wire rope securely. If you tighten it down too much, you run the risk of cutting through the rope.

Continue attaching your wire ropes to your centerpiece until they're all attached. You should end up with the underside of your baseboard looking distinctly spider-like at this point with your tentacles attached at 8 points around the center shaft at an equal distance from each other.

Step 11: TESTING TIME!

Now comes the fun! Plug in your motor and watch your tentacles come to life for the very first time!

Turn your motor off and on and adjust the tension of each individual wire rope using your stop swivels until you’re happy with the movement of your tentacles. (side note – in the photo above you can see I am holding the motor cable in place using two cable guides. This made it much easier to work on as the motor cable wasn’t flopping around.)

Here is how the whole thing looks when it’s finally moving but not yet skinned...and that means...

Step 12: SKINNING THE TENTACLE BONES

Using your polyfill, place small bunches in between the gears of your tentacle mechanics, making sure to include only enough to help give the silicone shape but not inhibit the movement of the tentacle.

(For ease of photography, I actually did this step with my tentacle mechanics removed from the base, but when you’re assembling yours, leave them attached and wired up.)

Slide one of your silicone tentacle skins over your polyfill wrapped mechanical tentacle and using your scissors, carefully cut up the side of your tentacle along the line where the teeth are. You want a flap that’s approximately an inch and a half long.

Make sure that the tentacle skin is still long enough to fully cover the mechanics inside. You’ll be using these flaps to help secure your tentacle skin to the baseboard. Here is how it looks with the tentacles attached to the baseboard.

Continue installing your polyfill and skins until all your mechanics are covered.

Per the pink diagram: To secure the tentacles to the backboard, poke a small hole in the back flap of your silicone on both sides of your newly assembled tentacle. Pass a screw and a nylon washer through that hole and then repeat the process with the tentacle directly next to the one you just prepped so two tentacles right next to each other share the same screw and washer. Bolt them to the backboard using a nut and by following this diagram – again with two tentacles each sharing one screw and washer.

Per the brown diagram: To secure the back of the tentacle, repeat the process you just did with the nylon washer and screw and poke a small hole in the center of the back flap and secure it to the board. For these, it’s one screw and washer set per tentacle. No sharing here.

As you can see in the last photo, where each tentacle sits next to its neighbor, they’re sharing one screw and nylon washer and where they are secured in the back, each gets their own personal screw and washer.

Once again, as you install your skins, plug in your motor and make any adjustments to the tensions wires under your plant to ensure the tentacles are moving how you’d like.

Step 13: ADDING THE GREENERY

Once you’re happy with how your tentacles move, it’s time to start decorating!

As you can tell by the photos in my tutorial, I got a little eager and started early, but trust me when I tell you, save this for the end. It’s such a pain in the butt to try to do adjustments while simultaneously trying not to knock moss off or leaves…keep it simple…save the decorating to the end.

Using your hot glue gun, start gluing down your reindeer moss, covering all the white of your cutting board.

To help hide the motor in the middle, I cut a tennis ball in half, jammed a clump of faux agave leaves in the middle, and then covered the ball with moss and glued the whole thing to the motor.

To give the urn the look that it was dripping with greenery, I glued String of Pearl plants all around the inner edge. I also glued down individual agave and aloe leaves (all faux) around and in between my tentacles to help fill in any empty spots.

Finally, I took my left-over speedometer cable, painted it green, and attached them to plastic spiders I’d also painted green using the Plastidip. The naturally springy nature of the cable makes the spiders bounce up and down realistically as the plant moves.

To attach the spider springs, I created a loop in the end of the speedometer cable and screwed them into place, sharing spots with some of the center screws I’d used to secure the sides of the tentacles down to the backboard.

Continue decorating your plant until you’re happy with how she looks. Make sure to occasionally stop and plug her in to ensure that nothing you’re doing decorating wise inhibits the movement of the tentacles.

Step 14: TIME TO ENJOY ALL YOUR HARD WORK!

And that’s it! You should now have your very own fully-mechanical, never-needs-watering, might-potentially-eat-the-dog-if-you’re-not-watching-carefully South American Strangler Vine!

To really have fun with her, I hooked her up to a simple motion detector that plugs into a wall socket. Now when you walk past, she’ll slowly start waving her tentacles at you.

While this is an incredibly heavy build and labor-intensive (it took me 3 months from start to finish but that included trial and error, lots of starting over and tweaking) the end result is so worth it!

I hope to see other versions of my own Cleopatra on here and if you make her, please share photos!

Oh, and I promise, I haven’t forgotten about those spare tentacles you may have ended up with after pouring your original 8. Hold onto those…we’ll come back to those in another fun

Happy haunting!

Halloween Contest 2019

Eleventh Prize in the
Halloween Contest 2019