Sans and Papyrus went off to Grillby's after Gaster told them too. The moment they got there they where welcomed with open arms, Sans ordered up began cracking stupid jokes that seem to annoy Grillby but the entire bar was laughing so hard very few people could stifle a breath, Sans was so happy to see people loving his jokes and Papyrus and Grillby seemed utterly annoyed by the whole Punny shenanigans. The two ordered up a plate of fries and burgers and the two boys where laughing and enjoying themselves and Gaster still hadnt caught up with the two of them, Sans began to worry but did not think much of it; as Papyrus paid and the two ran out into the snow and the two ran around utterly enjoying life but soon all this would fade to black as the crystals began to shine which meant it was getting near night. The boys returned home "dad we are home" Sans called

 But no one came.. 

"I think dad's probably busy with work. Can you read me a bed time story?" Papyrus was a little saddened himself that dad didn't show but Sans smiled at his brothers request "of course buddy, go get your jammy's and ill read to you in a few moments. I got to take my medication" Sans patted his brothers shoulder and the two left off to do there things. 

It was late at night a little after 12:30 The Underground was asleep and so where the skelebros, Gaster quietly moved from room to room making sure Papyrus was asleep before returning to the door just outsides Sans' room, the serum in his hand. The red vile stained the inside of the syringe "It's time... im sorry my boy " he enters Sans room who was sleeping, he was laying on his stomach and was snoring softly making little cooing noises in his sleep. Gaster felt his throat tighten a little hesitance as his eyes felt strained as he stood next to his son who was sleeping so peacefully.

 no... He's not my son... He's my c-creation.... He's not my child... He's... He's my son... He is my baby boy... Papyrus is my baby bones and so is Sans... Oh god.... Gaster backed away from the bed stifled a breath and teleported into his room and disposed of the serum and needle to be sanitized tomorrow. Gaster began to cry midnight purple tears I tried to kill my own son He covered his mouth as he sobbed grossly curling up into a ball and sobbing in anger and sadness..

I am not a man, or a mouse. I am a monster! Gaster was overcome by shame and grief. He did not sleep at all that night and continued his research into time travel so it seemed like he had been busy working and not attempting murder. Gaster cried out in sadness as he could almost hear papyrus the next morning sobbing in grief and sadness to find his brother dead in his bed. Gaster felt overwhelmed but somehow he managed to pass out on his desk in the lab... 

You Idiot...