Just as he predicted, Sans didn't really sleep, but it was nice to have Frisk curled in his lap.

Before their talk, he would've flushed a bit at having her so close to him, but after that emotional draw out, he didn't have the energy to be flustered. He was content just relaxing with her snuggled against his chest and watched her closely throughout her sleep for signs after another nightmare. Luckily when they were sleeping together like this, they seemed to go away, at least from what he'd seen so far. But he knew good and well there was an exception to every rule.

Papyrus left early, whispering a quick goodbye as he'd tromped quietly as possible through the house and out the door. And then it was just them.

...

Wasn't it?

Sans couldn't shake the feeling he was being watched. That they were being watched.

It wasn't like the other day when Alphys had crept up on them. It felt like there was a condescending spectator, spying on them with obvious malice.

Maybe it was just his imagination...

A loud crackling sounded behind him and Sans instantly whipped around to look over the back of the couch. His eye sockets widened in disbelief as what appeared to be a tear in the middle of the wall behind him sealed itself shut.

What the hell? What was that? A glitch? A tear in reality?

Sans was no stranger to the theory of other realities outside of this one, but never before had he come into contact with any of them until now. Was it possible for other realities to come into this one and interact with them? And if so, why were they just stalking around? Was there a reason they were being so secretive?

They needed to get out of the house.

Sans didn't feel safe with God knows who watching him. Granted, he knew that if they could watch him here in his own home, they could probably follow him anywhere, but there was just something unnerving about staying here after catching them in the act.

Without wasting another moment, Sans teleported away, landing him and Frisk at his post in Waterfall. 

He didn't check to see if he'd woken Frisk, just kept his eyes open and scanning for any signs that they'd been followed.