Both skeleton brothers were inside a laboratory cell, where they get often tested on experiments... the experiments are... rather not good to mention.   Papyrus: Hmm... i guess we don't have anything to do to cure our boredom, sans...   Papyrus says in a gloomy voice.   I guess so. Sans responds.   Suddenly, the laboratory door opens and someone steps in.   Sans: You again... G-... what? Sans with an aftertone was confused. He was expecting a torturing experiment than someone else.