horror sans is a skeleton, he has a hole in his skull who was made by undyne when he was attacked by her, he keeps his cleaver in there, he has blood-stains all over him from his victoms, his right eye glows red with a black pupil, his left eye dosent glow, his eye stops glowing when hes serious, he likes to cut off a arm or a leg of a victom and make "head dogs", head dogs are legs or arms, skinned and put in a hotdog bun, he likes to eat them and sometimes force feeds his victoms them,