Personality. Gaster is a dark, and cruel entity scattered across space and time. Mysterious, and he likes to do science experiments to entertain him. When he's taking a break or something he'll lock you in a cell with lazer bars. A cruel person that mostly experiments on people, mostly Sans and Papyrus. He's not a good person and he likes to watch people suffer as he experiments on them to get data, and isn't good at affection or anything like that, he doesn't kill his experiments either though.