Warning: There may be inappropriate things in this. Reader discretion is advised, so read at your own risk. I don't own anything but the story line in this. Everything belongs to their rightful owners. You're playing Undertale and just finish the normal run. When Sans calls Frisk, your phone starts ringing. You answer it and hear Sans on the other end. You two start talking for a little bit, then your door opens to... Who's at the door? Read this to find out.