"S-S-Sans! W-w-w-what are y-you doing here?!"

"To hell with that! WHY are you here," Undyne screeched as she pulled a spear from beside the couch and pointe it at Sans, non threateningly of course.

Sans simply laid back against the couch, his ever present grin taking on something sinister. "Nah, I think the real question here is, 'why aren't you training with Paps?' After all... He was super excited about it this morning," he asked calmly, he left eye blazing.

Alphys leapt back, glaring at Undyne accusingly,"B-but I-I-I thought you s-s-said he never s-showed!? U-Undyne! W-what's going on?!!"

Immediately, Sans honed in on the fish warrior, ready to kill. If anything happened to Papyrus on her watch, he wouldn't even hesitate to unleash a load of gaster blasters on her. And as she adverted her eyes to the floor and slowly backed down, Sans could only take it as guilt.

"D-dont worry, he's fine. He went back home like ten minutes after he got to my place, alright?" 

Sans wasn't buying it.

Without another word, Sans summoned a gaster and aimed it at her. Oh her face was priceless. Sans was never really an aggressive guy, but when it came to Paps, he would watch the world burn to keep his little bro safe. However, for now, Undyne was his only target. Alphys obviously had no idea where Paps was or she would've spilled by now.

Undyne backed away, holding her spear out defensively,"Wait! Wait! Wait!! I told you he went home! Just go and look!.... Wait! No don't! He's there though! I swear!"

The gaster opened its jaw and began to charge it's beam. "Why," he spoke dangerously.

".... I........ I can't tell you..."

"Undyne, my patience is wearing thin."

Alphys squealed and ducked behind the couch,"P-please, Undyne! J-j-just tell h-h-h-him!"

Undyne growled loudly, slamming her spear into the floor,"Fine! He's making a surprise for you and Frisk! Happy?!"

Suddenly the gaster dispersed and Sans eyes were back to normal. He relaxed back into the sofa with a carefree grin," See now, was that so hard? What's the surprise?"

Alphys peeked over the couch in surprise, still a bit too wary to actually sit on it. Undyne was exasperated and flabbergasted. One second she was fearing for her life, and the next she supposed to be calm and comfortable? Screw that! In the heat of the moment she snapped her spear over her knee with a growl,"You're insane! How can anyone stand you? How can Frisk like you?!"

Undyne slapped a hand over her mouth and Sans just stared at her for a long time.

" What?"

This time it was Alphys that spoke up,"Y-you really can't tell? It's pretty obvious to, like, everyone!" Sans turned his gaze to the scientist, staring at her in disbelief before suddenly bursting out into laughter. The other two just watched him with confused looks as he finally gained his composure and stood up.

"You two really know how to tell a joke. But come on now. I came over here to check on the status of the barrier," he said casually as he started walking around and looking through Alphys' piles of junk with no real interest.

Alphys looked to Undyne concerned, then back on to the wondering skeleton,"But, Sans, we're not joking! She really does-"

"Alphys, do you have any new information or not?"

The yellow monster shrunk back a bit, sensing the sudden change in his mood. She looked down at the floor and sighed softly. "No. I haven't found a way to cross through the barrier. Nothing is working. Even a synthetic human soul couldn't do it.... But, our synthetic determination serum has somewhat weakened it."

"Good, Asgore will be glad to hear that", he quipped, voice back to its normal lazy tone," I'll be back in two weeks to check your work again. Let me know if anything changes before then."

He didn't wait for them to respond, just shortcutted away with a wave goodbye, his mind and soul racing around their words. Frisk? Like him? Ha! She'd been around him long enough to discover what he was like, his personality wasn't exactly desirable. No, they must be confused.....

...Or playing some cruel joke on him.

Appearing back in the hallway he'd left in, Sans slowly walked upstairs. At first he really didn't think anything of the silence echoing in the home, at least until he made it into the main room to find neither Frisk nor Toriel.

It spooked him, especially since the home was never quiet.

"Tori? Frisk," he called out, looking around for the two.