Sans: Heh, my old man and I have a joke where everytime I say "love you" he'll say "Disappear!" And press against the closest wall
Toriel: Oh? //smiles// That is adorable
Sans: Yeah.. but we only did it once..
//flashback//
Sans: Hey Dad!
Gaster: Yes?
Sans: Love you!
Gaster: Disappear! //fades away//
Sans: ;-;