Bitty Dream Sans can travel into the dreams of his owner, and also fight off nightmares either with or without the assistance of his brother, Nightmare Bitty Sans, who absorbs the negative energy and emotions with ease. He is cheerful and positive. Very protective of his owner. Bitty Nightmare Sans can absorb negative emotions like fear, depression, anxiety, anger, despair, and so on, and when he does, a bit of purplish-black goop leaks from his eye sockets.