A Body Inside of Funtime Freddy
During Five Nights at Freddy’s: Sister Location, you can find blueprints of the different animatronics in the game, which is pretty cool. One of them, however, houses a pretty dark Easter egg. If you look at the blueprint for Funtime Freddy, you will see a child located in its stomach area, which is marked on the blueprint as a Storage Tank.
This is pretty macabre, and adds credence to the belief that these animatronics are specifically killing children. That theory is supported even more by the fact that it has a built in Voice Mimic/Luring device. If these animatronics were truly friendly, there would be no need to “lure” anything, much less a child.