I will show you how to make a funny costume, using cheap materials, and which is also interactive: it has a "raining" effect!

This is an easy and very cheap project you can finish in about 10-15 minutes. Actually, I made it only with materials I already had at home, because I had to wear a "funny hat" at a party, which was about to start.

For my surprise, I was chosen "best hat ever" in that party, and I won a symbolic prize! More than a 10 min effort should deserve!

Step 1: Materials and Tools

- Plastic bottle caps: you need two different sizes, so one cap should fit into the other one. I had to use blue colored caps, because those where the ones I had at home, but the perfect colour is white or grey, the same as the cloud.

- Plastic transparent tube: the thinner you could find. in fact, mine was too thick, but again it was the only I had at the moment. The thinner it is, easier will the water flow.

- Wire

- A white or grey thin plastic sheet. You can also use cardboard and cotton, as I did, but it isn't the best idea, because it becomes wet so easy. In fact, my hat was collapsing after the party.

- A water spray: choose a small one, so it will be more comfortable to carry in your pocket.

- An umbrella hat. I already had mine, but if you don't it's easy to find and very cheap. I bought mine in a local store time ago for 2€ (about 3$), and I've also checked at internet stores, where they are also very cheap (3-5$).

- Scissors

- Hot glue

- A needle or a pin

- Pliers

Step 2: Making the Shower Cap

First of all, take the largest bottle cap and make several holes in it using a needle.

Then take the smallest bottle cap and make a bigger hole in the middle of it (for that you can use an screwdriver, a drill or a soldering iron). Make sure that the hole has the same diameter as the plastic tube, so it fits tight in it. Then attach the end of the tube to the hole using hot glue.

Use some more hot glue to glue the two caps together. Leave no hole but the ones you did with the needle!

Step 3: The Cloud

As I previously said, I made my cloud of cardboard and cotton. It looks very nice, but I discovered that it wasn't the best idea, because those materials become wet so easily, and that can ruin your work! Fortunately, although that problem, it lasted all the party. But didn't survived for the next one.

For that reason, I think is better to get a thin plastic sheet, in white or grey colour (remember, we're making a cloud).

Simply cut out the shape of a cloud in the sheet and make a hole in the middle, the same size as the diameter of the tube. For mine, I used cotton and hot glue for the final touch.

Now you can attach the cloud to the shower cap, passing the tube trough the hole in the cloud and using some hot glue so the cap and the cloud are glued together.

Step 4: Attaching the Cloud to the Umbrella Hat

Use a piece of wire, thick enough to support the cloud without bending, and attach it to the top of the hat. Simply make a loop around the top plastic piece and adjust it with the pliers. Make another loop at the top, as showed in the image, so the tube can pass trough. Note that between the shower cap and the wire loop there should be located the cloud, but in the image it doesn't appears (I hadn't attached it yet when I took the picture).

Then, using thinner wire, attach the tube to the thick wire, as showed.

Step 5: The Water Pump / Water Spray

Take the end of the plastic tube and the water spray. Put a small amount of hot glue around the end of the tube, be careful so you don't cover it completely. Then attach it to the water spray. Hold the two things together with your hands until the glue dries. Then cover the junction with more glue, so the water wont come out.

Step 6: Done!

Now fill with some water the pump and try it. The tube is full of air, so you'll have to press the pump some times before the water reaches the cap. The thinner the tube is, the sooner the water will flow.

For the rest of the costume, you only need to put on your raincoat and a pair of boots! Now you can go soak the people, being safe under your umbrella hat.

If you liked this instructable, or if it saved you as your last chance of having a cheap and easy costume this Halloween, please vote it for the Halloween contest 2014!