Being a fan of easy awesome Halloween Projects I thought I would share this cheap and easy Rotten Pumpkin creation. They can be made start to finish in as little as an hour and cost only about $20.00 to make.

Supplies

A Pumpkin that is solid Styrofoam with a plastic outside; not one of the hollow ones. You can get them cheap at Walmart and Michael's.
Flat Black Spray Paint
Small bottles of Acrylic Paint (Black, Green, and Brown)
Dremel Tool if you have one (makes carving much easier)
Razor or X-Acto Knife
Heat Gun
Computer with a printer if you aren't good at making pumpkin faces like me.

Step 1: Pick a Face

Since I am not the greatest at carving pumpkins I like to get my templates from the internet. My favorite site is www.pumpkinpile.com. They have a great selection of free templates. Depending on the size of your pumpkin you may have to scale the image to a size that fits. Using tape, position the template just like you would to carve a real pumpkin. Carefully trace out the pattern, cutting through the plastic of the pumpkin. You do not need to cut very deep, just enough to cut the plastic. Once you have finished you can remove the template. Using the X-Acto knife to lift the edges carefully peal away the areas that were traced out.

Step 2: Carving Time

The carving part is not that complicated and can be done using just about anything that will chew up Styrofoam. My tool of choice is a Dremel Tool with a router bit. Depending on the size of the pumpkin you want to carve about a half inch to three quarters of an inch deep. It does not need to be pretty and even. A little uneven will actually make it look better in the end. If you are using a smaller pumpkin you may not want to go as deep as the eyes and nose may join together in the next step.

Step 3: Make It Rot

Now that you have a happy looking Pumpkin, it is time to make it ugly. First thing you want to do is open a window because you are going to be heating up plastic and Styrofoam which give off some nasty fumes. As easy as this step is it does take a little practice; so start on the bottom of the Pumpkin. Using a heat gun, heat the surface until it starts to form bubbles, once you see bubbles start to form move the heat away or they will pop and ooze out melted Styrofoam. Work your way around the entire Pumpkin until you have a nice bumpy looking texture. Around the eyes and mouth be careful not to melt the Styrofoam too much inside.

Step 4: Finishing It Up

The painting part may look complicated but I promise with very little skill you can make it look awesome (Trust me I am not an artist). Take the Black Spray Paint and a few Paper Towels and you are ready to start. Begin by spraying the paint right into the eyes, nose, and mouth. Notice the Styrofoam starts to melt? This will give it a bit of an uneven look which is good. Wipe off any over spray around these areas but do not worry about getting it spotless. You will have spots of white which we will clean that up later. Next you want to work in sections on the rest of the Pumpkin. Once again for practice start on the bottom. Spray paint it Black and then gently wipe it off with paper towels. When you do this it will leave the Black Paint in the low spots and darken up the high spots of the bumps. Continue working your way around the entire Pumpkin until you have the coloring you like. If you are using a Pumpkin with some green in it like the pictures you will get a nice moldy look to it. If you started with one that is just orange mix a little green and brown paint to make a moldy looking green. Using a 1 inch wide paint brush dip just the tip into the paint. Take a scrap piece of cardboard and brush the paint off until there is almost none left on the brush. Using quick back and forth strokes hit some areas of the pumpkin. This is called dry brushing. You want very little paint on the brush for this so it will only show up on the high spots. You can now finish up the eyes, nose, and mouth with some flat black acrylic paint which will not melt the Styrofoam. I hope you enjoy this instructable and have a Happy Halloween.