The Dutch Hill Mansion Demon or The Plaster Man refers to the creature that attacked Jake during his second arrival to Mid-World through the door he finds in The Dark Tower III: The Waste Lands. The creature is one of the leftovers from when the prim receded. The demon protected one of the lesser magic doors that led into mid-world.
When coming through the door to Mid-World, Dutch Hill Mansion begins to warp, its boards and fixtures turning to become a demon. The Plaster Man meets his end after Roland releases the speaking house demon into the throat of the plaster man.