The Pillow Child is a character that bumped into Finn in the episode, "Puhoy." They told him to start running because the Blanket Dragon was terrorizing the town.
Appearance[]
They appear to be a Pillow Person with a giant white sheet draped over them. They also appear to have large teeth.
Personality[]
At the time, they seemed rather fearful of the Dragon, but they weren't panicking to a large extent.