Kids have no filter and a completely new and undeveloped context for socializing with others, which can make them simultaneously genius and terrifying at times. Most adults who aren't auditioning for Dexter know you shouldn't make passing comments about wanting to wear people's skin, or pluck out their eyeballs, but many young children just aren't there yet.
Whether they're trying to give you a compliment, or acting as a medium for a demon of some sort, children have the unedited ability to change the energy in a room with the mention of just one creepy thought that passed through their head unexamined. To add to that, children are extra sensitive and more open to the possibilities of ghosts and invisible worlds.
In a recent Reddit thread, parents shared the creepiest things their kids have (recently) said, and it'll make you wanna lock your doors whenever the school bus passes by.