Help! Halloween costumes to wear at work?

Tweet

Ok, there's a costume contest at work (I work in housewares in a retail-hardware type store), I need to find a really cool costume to wear for Halloween. The big catch is, we still have to wear uniform, which means ugly red tshirt and black pants. How can I have a really cool/original costume that will still allow me to move around easily, and nothing too bulky (I have to fit down the narrow aisles and be able to go up and down stairs all day)! Any suggestions, ideas? Please?