He is aggressive with others and quite hateful when seen in Snowdin. This is shown especially when he is around the player. He often teases the player which usually results in Flowey getting very annoyed. He is not as "evil" as most of the other characters are portrayed, but still believes in the "Kill or Be Killed" motto. Mustard is his favorite food, rather than ketchup. Sans can be harsh at times. He is not into puns that much, but he likes knock knock jokes.