W. D. Gaster x Reader Oneshots (Requests Closed)

~Yes, Daddy~

"Daddy! Daddy!"

(Y/n) turned away from her work and saw two little skele-kids running through the entrance of the lab. Her eyes trailed after them and landed on their target: Dr. Gaster, their 'dad'.

"No no no, boys-oof!" He held out his hands in defense before they tackled the scientist to the ground.

(Y/n) smiled. As assistant to the royal scientist, there really wasn't many things to smile about on the daily. Nothing except this.

She peered over a countertop down at her boss. One kid was attached to his torso, the other clutched onto his leg, hugging it.

"Alright boys, I think he's had enough." (Y/n) speaks up, giggling a bit.

They look up at her and smile.
"Hey (y/n)." Sans greets nonchalantly, waving to her.

Papyrus jumps onto the counter and launches himself into her arms. "Hi mommy!" He says, hugging her neck.

Groaning, Gaster gets to his feet, Sans climbing onto his shoulders. "Apologies, (y/n). My boys can get a little overexcited at times..." He said, reaching over to retrieve Papurus from her arms.

"I want mommy!" Papyrus clutched onto (y/n)'s shirt. Gaster blushed at this comment, wide eyes darting up to hers.

It wasn't a real surprise that Sans and Papyrus thought of (y/n) as their mom. Not only did she work for Gaster in his lab, she would often offer to watch the boys for him and keep his home in order/clean it for him if he was too busy to do it himself. It wasn't a big deal for (y/n), though. She thoroughly enjoyed their company, especially when it was their dad keeping her company...

"(Y/n) is pretty cool, dad", Sans laid his head down on top of Gaster's head. Gaster narrowed his hollow eyes and grabbed Sans under his arms. He sat him down and reached for Papyrus again.

"Come on, Papy, Mommy's gotta get back to work now." (Y/n) cooed, making the small orange eyed skeleton loosen his grip. She passed him over to Gaster.

She took a mental picture of this little moment. Dr. Gaster, both loving kids in his arms. Lord, it was so cute!

He walked over to the door and dropped the kids to their feet. He bent down to their level for another quick hug before he'd told them to go play and away they went, tiny bones rattling down the corridor.

Now he was looking at (y/n), giving her the kind of look that said: "Really now?"

"What?" She asked, shrugging her shoulders.

"Mommy?" He inquired, looking a bit amused.

(Y/n) giggled and perched herself up on the nearest empty countertop space. "Oh come on, at least they like me. And they absolutely adore you." She said, smiling.

Gaster sighed and rubbed the back of his neck. "Just..." He searched his words for a second. "I'm ok with them referring to me as a parent, but could you not encourage them to call you one, 'mommy'?" He asked smugly, going back over to where he'd been carefully mixing chemicals.

(Y/n) was taken aback by his use of her nickname and blushed a little. However...Two could play at this game.

"Yes, daddy."

Cue chemically induced explosion.

A/n: Yes, Undertale is a part of this lowly author's life now. I started playing the game almost about a week ago, but have been a part of the fandom for maybe a month now. And I love Gaster. There, I said it! Can't be helped...He keeps meeting all my standards! Xp Hope you guys liked this! :3