"PRINCE ASRIEL, I WOULD ADVISE THIS ROUTE NEXT!" Papyrus yelled loudly; looking down at the young monster. Frisk and Asriel had both decided to go as skeletons; much to Sans' and his younger brother's delight. Papyrus hadn't stopped 'nyeh heh heh' ing for a good hour at the masks and painted black clothing they both wore.
The gentle prince smiled up at the tall skeleton, "sure, Papyrus. Lead the way."
Even though night had fallen; none of the humans had caused any trouble for them. In fact; this seemed like the most accepting they had been. Perhaps it was the holiday... Sans blinked his eye sockets in surprise when his cell phone began buzzing. Were you calling him? He had told you to call if you needed anything.
He glanced at the display.
Undyne.
Picking up immediately, Sans held the phone to his skull, "what's up, undyne?"
"Sans, we have an issue."
He stiffened at her tense tone and his eyes met Frisk's. Both Asriel and Papyrus were shooting him confused looks.
"you guys go ahead; i have to take this." He told them with a smile and only when they turned away without any hesitation; chattering to each other happily did he teleport directly to Alphys new lab.
"FUCKING SHIT!" Undyne fumbled her phone and dropped it at his sudden appearance. Alphys was messing with her phone; trying to see if she had stored your tracking number in her contacts.
Sans' tilted his head and was about to crack a joke before Undyne got over her shock.
"Sans, _ is in heat."
If he had a beating heart; the skeleton would have sworn it had stopped beating at that simple sentence. His whites looked around the lab anxiously.
"why did you call me here then?" He asked in confusion.
"Because she isn't here!" Undyne said anxiously.
"what...?" Of course you were here. Tori would have told you the basics of what all female monsters were schooled in before they fully matured. From what he remembered of the lecture from Dr. Gaster; every female monster went into heat and had to be helped by someone who could stabilize your magic. Scientists usually had the equipment to mimic a mate's hold over your core. It was synthetic and wouldn't help with the actual heat, but at least the monster would be in control.
"She's lost somewhere out in the forest."
No...no, this was the worst possible thing. His left eye socket erupted from anxiety and he growled lowly at the former Royal Guardsman.
"why are you still here? she has gravity magic!" His magic was humming and his fangs were bared in frustration. Didn't they understand the severity of the situation?!
"Sans, calm the fuck down," Undyne made a face at the magic sizzling in the air. Damn, she hadn't known his magic was this potent...
"N O." His voice was hollow and deep with a snarl, " R!"
"Do you want a babybones or not?"
The question caught Sans off guard; the air becoming less heavy, "what...?"
"I asked her if she wanted your kid and she said yes."
You...you...
"she...she wants a baby?" His anger felt like it had been doused in water, "...with me?"
"OF COURSE YOU, FUCKING NUMBSKULL!" Undyne yelled impatiently. Later, she would think his incredibly shocked expression was cute, but right now she was worried about you. And damn her if Sans ever heard about it.
Sans' glowing eye seemed to be staring into some middle space as he thought. Gaster had all but left him to raise Papyrus on his own. And his little brother only came to his waist when their 'father' had vanished into space and time. He had experience with it...
But he was floored that you wanted a child with him... Sans had the blood of countless battles with Frisk (who he now knew had been Chara) on his hands. He had accepted his sins, that he had killed over and over; sometimes not in the name of judgement. But his own fear.
...He had never considered that you would want to start a family with him; but now that the notion was in his head, as a full possibility...
Sans wanted it. He wanted to take care of you and a baby, his baby. He wanted to make Papyrus an uncle.
He wanted to create something good with you. You had freed him from the nightmare of repeating timelines. The underground was now on the surface. Sans wanted nothing more to give you everything you desired.
His gaze focused on the tense couple and he grinned, "don't wait up."
Sans was gone in a blink and Undyne started as her girlfriend squealed happily.
"I ship that so hard!"
The sea monster chuckled, blushing a bit, "guess we should start making bets on the gender, eh, Alphys?"