Mr. Crocker is the teacher of Timmy Turner, Chester, A. J., and many others. He was the previous owner of Cosmo and Wanda. When he lost them he got his memory wiped. He later remembered and devoted his life to prove fairies are real. He hasn't had much luck with that though. He detected high magic around Timmy so he always acuses him of owning fairies. There are other interesting facts about him including he is hunchback, he lives with his mom, and he has invented few fairy hunting gagets that work.