Undertale-A Fight To Remember

It was a beautiful day outside, Frisk was playing with papyrus in a intense game of "Stareing contest".
Toriel was takeing care of the ruins with sans,Mettaton hanging out with his cousin Napstablook and alphys watching anime with undyne. But there is a person....Lost in the beyond....no one is there exept for him
He had fallen into a black "Void" Screaming for help his lab assistants tryed to help him..but couldnt who was this man? Why its..... ☝♋⬧⧫♏❒(W.D. Gaster)