My favorite ones I did are in the list below.
Note: Random Order.
1. Grim Reaper. Had a skull painted on my face. Never opened my mouth because the teeth were painted on my lips.
2. Garbage Can. Had an extra large size with a slot cut out in the front where my chest was. I had a garbage bag put around a hole with an "Insert Here" sign. That way, the candy would be in there with me. Genius.
3. Old Style Green Army Man Toy. I was painted totally green and had my friends drive me around in the trailer of a mower. They made sure to get me candy. One of the people refused because he didn't think I was real. So I pointed my airsoft gun at him and shot my friend in the back.
And last but not least,
5. Scarecrow. Did the whole Trailer thing except I stood on a step and hooked my arms over two hooks. Didn't hurt much and my friends got me candy once again. Scared the s**t out of people when they walked by. I would stand there, totally still until they walked by. I would quickly jump out right at them. Made one kid drop his bag.