Babusu

Babasus are found in some palaces in the Dark World. They live in the walls and come out sometimes to attack you. Their tactic is coming out of the holes and slithering across the room. Sometimes they'll have two holes that are parallel with each other on the opposites sides of a room, and they travel between them. When you see a sparkle in a hole in a wall, prepare your sword since that's a sign that one is coming out.