Sans

he is a joker, if you decide to kill a lot of people he will kill you will say "it's time for judgment....the birds sing....the flowers bloom....on days like these....people like you...WOULD BURN IN HELL...." and then a blue flame will come out of his left eye and he will become very serious and a little joking, his abilities are to control the bones and throw more than 1000 bones at the same time and launch laser beams from different directions of blue color, if he throws bone bones blue color and you stay still they won't hurt you but if they throw white bones at you they are totally hostile, in addition to being able to control your body with telekinesis and most of the time they spend telling jokes, their friends are toriel, Muffet, asgore, undyne, Alphys and her brother Papyrus who she likes very much and likes to tell a lot of jokes and if you mention that you killed Papyrus he will tell you "DIRTY KILLER OF BROTHERS..."