A chestburster from Alien
What makes Donovan Clark's alternations of money so impressive is that they appear to leap off the paper. After he works on a one dollar bill, George Washington is ready to burst out of your chest or leap into action into a three dimensional world.
Sometimes he leaves them as tips. Wouldn't you like to have one?
Lion-0 from ThunderCats
Leatherface from The Texas Chainsaw Massacre
Chief Wiggum from The Simpsons
Soundwave from The Transformers
-via Nerd Approved