A mythological horse demon which haunts the entire Northern United States. Legend depicts it as being long and snakelike, with the head of a horse and one hundred legs.
It is rarely seen, as it only moves at night. The only sign of it's movement is the sound of an entire heard of horses galloping.
Person 1: "Did you hear horses galloping outside last night?"
Person 2: "Yeah, but I didn't think there where horses around here?"
Person 3: "It was probably the Centipede Horse."