Killing Xanathar

You decide to listen to the skeleton because he seems really eager to ask you. "What walks on two legs, then four legs, then lies motionless on the floor?" asks the skeleton. As you try to think of an answer, the skeleton yells, "YOU! NYEH HEH HEH!" and stabs you in the heart with his sword. You fall onto the floor realizing that the riddle was just saying you were going to die. Right before you die, you hear the skeleton chuckle to himself as he pulls a plate of spaghetti out of his rib cage.