Hide and Seek ending / spoiler
DeNiro is Charlie. Dr. Callaway has a split personality. As "Charlie" he killed his wife and others. Emily (Dakota Fanning) knows about the two personalities and witnessed her mother's murder, but she plays along with her dad's dual identities in order to keep him from freaking out. Emily goes and lives with Famke Jensen's character and draws a picture of them, all playing happy family. but in the final shot, we see Emily has drawn herself with two heads (so now she has two personalities!)
Submitted by Stellabella
