A boy I once taught came as a highway. He dressed all in black and put strips of bright yellow utility tape down the front of him. Then, he hung Hot Wheels cars at varying lengths down the front of him, on either side of the tape. It was very cute.
One year, my assistant and I went as the tooth fairy (me) and a dentist (her). I wore an old bridesmaid dress and I made a crown of teeth and a wand with a tooth on top, using poster paper and glitter. She had a white lab coat on, one of the things doctors/dentists wear on their heads (with a light attached), and she carried a drill.
One year, I was a panda. I wore black sweat, a white shirt, balck sneaks, and a black hooded sweatshirt. With the hooded sweatshirt, I put my arms through the sleeves and the hood on my head. Then I zipped it up in back of me, so the whote stomach showed. I made ears, and I painted my face like a panda. If you have access to it, you can carry a stalk of bamboo.