Which words won't work in Scribblenauts?

It's pretty tough to find a word that won't be recognized in Scribblenauts. There were five people from that provided the developers with assistance in researching words for six straight months. Because of the amount of time spent, the game can transport even a giant enemy crab or Leroy Jenkins into the game. But won't about words that can't be viewed in Scribblenauts?