Well…this happened.

This is another ABDL!Sans story. I just love this kind of stuff. I may start doing other oneshots with different characters besides Sans if you all would like.

Also…Sans and Gaster kind of act a bit OOC but I hope you guys don't mind.

I don't own UNDERTALE. I am not Toby Fox.

Sans woke up sweating and breathing heavily.

He looked around the dark room as he clutched his blankets tightly. He whimpered as a set of red eyes along with demonic laughter flashed in his mind.

He then turned to the digital clock by his bedside.

Midnight.

Tears welled up in his sockets as he sucked on his thumb.

He had had another nightmare. And he always hated when that happened.

The death of his brother. The kid…Chara…

He hugged his blankets tightly and let the tears rolled down his cheeks.

Why did he keep having dreams about these things? All that stuff happened before the reset.

He should be happy.

He should have forgotten about it.

Why are they still haunting him?

His head began to ache as he kept crying. He wanted Papyrus. He wanted him to come and make sure he was okay.

But…Papyrus was out. Him and Frisk had left for a sleepover at Undyne's. That left him all alone.

He hugged himself and cried as the thought of his brother dying before him came back into his mind.

"Why would they stop…?" he cried.

It seemed as if it he was the only person who knew about the resets. Everybody – even his own brother – had no clue as to what he was referring to.

This would happen time and time again and yet everyone else's minds were drawn to a blank every single time.

He sniffled as he continued to suck on his thumb.

During this period, this would be one of the things to calm him down. If only his brother was here…

Suddenly, he briefly heard the front door open and slam shut. His shaking continued.

Who would be coming into the house this late at night?

It couldn't be Papyrus. He would never leave a sleepover especially this late at night. It couldn't be Frisk either because they were with his sibling. And they hated to go out in the dark.

Nobody else would want to come in his house but him and the two he just mentioned. They had nothing valuable so no stupid robber would want to come in to take anything. No one hated the brothers either so no one would want to kill them.

No one except…Chara?

But…that couldn't be! This wasn't another reset was it? Did Frisk go evil on Undyne and Papyrus and was now going after him?

Quickly, he stumbled out of bed and finally took notice that his pants were wet.

He felt the plush cotton of his clothes and mentally cursed himself when he felt a warm spot in between his legs.

Tears were pricking his sockets but he quickly wiped them away.

The enemy shouldn't see his opponent cry. It was a sign of weakness.

"Sans?"

He jumped.

That sounded nothing like Chara. It was too deep and older. And it wasn't Frisk or Papyrus. Their voices were lighter and the human didn't even speak.

The skeleton looked up and saw a face he hadn't seen in years.

Sans finally spoke. "Dad…?"

Gaster looked around the room and then back at his son.

Sans was a mess to say the least. He was crying and had a bit of snot poking out of his nose hole. As he sniffled, the older male saw that his light blue pajama pants were wet and so were his sheets. He was also shaking a bit, as if something had spooked him.

The taller skeleton's eyes softened. "Whatever is the matter Sans?"

"I…" he started as he rubbed his arm and looked to the floor. He sniffled again. "It's dumb…"

Gaster walked up to the little skeleton and bend down. "If it was dumb, you wouldn't be crying." He put his finger under Sans' chin, making him look into his father's caring eyes. "Tell me what's the matter."

The tears in his son's eyes returned as he hugged his dad. "I…I had a nightmare…"

The older of the two smiled lightly before lifting Sans up and walking out of the room.

"Where…where are we going?"

His dad didn't reply and snapped his fingers, causing them to teleport to his old work room. Sans looked around as Gaster then walked into a separate room.

It was the scientist's bedroom.

He had then put Sans on the bed before walking into the closet.

The little skeleton looked around the bedroom and saw that everything was clean. There was no dust in sight and was as neat as ever.

He yawned as his father came back with some supplies in his hands. Sans had noticed the diaper and the baby powder first but then his eyes shifted to the wipes and baby lotion.

There was also a piece of clothing that was baby blue in color.

"You poor thing…" the father soothed as he silently told his son to lay down.

Sans did just that and blushed as Gaster put the stuff down and set to work.

He took off the young man's pants and set them aside. He had then put some of the lotion on the tips of his fingers before rubbing it on the bones that made up Sans' lower region.

The little skeleton was blushing deeply as this was happening. Not because of the feeling but because it was so embarrassing.

He wanted to cover himself just in case anyone came in but then remembered nobody else was here. And so, he relaxed.

"Take this." His father instructed, handing him a pacifier.

Sans took it and popped it onto his mouth, sucking on it contently.

"That's a good boy~!" he cooed, rubbing his son's cheek gently. "You're such a good baby~!"

Sans smiled automatically. He didn't know why but he was kind of enjoying himself.

Gaster lifted his son's legs up so he could slide the diaper underneath him. He then sprinkled a bit of baby powder on his pelvis and the infantile garment before putting it on him.

The scientist smiled at his work and then opened up the baby blue cloth to show off a onesie with a teddy bear on the front.

"Sit up please." He demanded calmly as his child did just that. "Arms up."

Sans complied just as his dad put the article of clothing over him. Gaster had then picked him up so he could button up the bottom of it. He then stood back to admire his handiwork.

"You look absolutely precious Sans~!"

He blushed and then shyly said behind the pacifier. "T-Thanks Daddy…"

"Are you ready to go back to sleep?"

At the mention of sleep, he yawned as a reply. His dad nodded, knowing what that meant.

He picked him up and kissed his cheek before gently placing Sans in his bed. Gaster then went to the other side of it and crawled in after him. After that, the scientist pulled the blankets over then both.

"Cozy?" The older skeleton asked, bringing his son close to him.

Sans yawned and sleepily nodded. He hugged his dad as the scientist gingerly placed his son's pacifier in his mouth when it looked like it would fall.

"Good night Daddy." He said, snuggling close to his dad's chest and hearing his heart beat.

Gaster kissed Sans' forehead and smiled as he replied.

"Good night my baby boy~!"

I'm dead. I have died of cuteness…