"...Sans?" Asriel spoke slowly, knowing that in this timeline Toriel did not know Sans was the one exchanging jokes with her through the door.

'Sans' slowly turned, swinging the key around one hand with a bit of magic.

"HI THERE! DID YOU SLEEP WELL? HOPE YOU DON'T MIND ME USING YOUR FRIENDS VESSEL FOR A WHILE, SINCE, YA KNOW, YOU DIDN'T WANT TO SHOW ME THE SOULS. BUT THIS GUY RIGHT HERE WAS HAPPY TO MAKE A DEAL WITH ME! ISN'T THAT RIGHT, SKELE-PUN?"

Sans struggled to speak, and had to keep himself from calling Toriel's name, he technically wasn't supposed to know what she looked like yet.

"R-run..." He was barely able to stutter, his eye started glowing again.

"That voice...!" Toriel whispered, reaching out a gentle hand.

Sans saw Bill reach out to teleport again-or possibly do a magical attack on Toriel and Asriel—and started struggling even more than ever. Shaking, switching back and forth between bits of Bill's and his own voice, flashes of magic fading in and out, until Bill called out "ENOUGH" in his demonic voice, then cleared his throat and went back to his usual playful one.

"LOOKS LIKE THIS GUY'S GOT SOMETHING TO SAY, I'LL GIVE YOU A BIT MORE CONTROL FOR A MINUTE, BUT REMEMBER THAT I'M WATCHING." Bill didn't completely give up control of Sans's body, just stopped talking to let him speak for a few minutes. A few minutes that Sans had no idea how to spend.

"H-hey…knock knock…?" Sans didn't have time to think of a good pun.

"Who is there?" Toriel followed along with the joke, whispering softly.

"T-that guy." Sans was mentally face-palming himself.

Toriel couldn't help but laugh a bit. "That guy who?"

"That guy who…always tells knock-knock jokes, at the door. I'm, uh, Sans…Sans the skeleton." He couldn't think of anything else to do other than an introduction, before explaining anything else.

"Ah…so it is you. I knew I recognized your voice from somewhere. Tell me, Sans, who's this little creature speaking from you?" Toriel tried her best to remain calm and get to the bottom of things, but anyone could she see was starting to tremble.

"This weirdo? Well…uh…" Sans couldn't just say 'I made a deal with a literal demon of time and space so I could bring back you, and the rest of my friends, back from the dead. Oh, and you were all dead in the first place because of a time-travelling genocidal devil child.'

"…guess I was just in the wrong place at the wrong time." Sans sighed, he really needed to be serious now, if he had any hope of saving everyone. "Look, you need to find the souls and take-" The voice switching started again.

"SORRY PAL, TIME'S UP! WHAT MADE YOU THINK YOU WERE IN CONTROL?" Every time Bill's voice turned deep and bone-chilling, Sans's eye glowed brighter than it ever did before, as it was now fueled by the influence of two ridiculously powerful beings.

Asriel felt the soul inside him ache for justice. "What do you want with the souls?! My dad…Asgore…he's gonna stop you!"

"AWW, LOOK AT THIS KID, SO FAITHFUL TO HIS FAMILY. I BET YOU'D HATE TO SEE ANY HARM COME TO THEM, HUH? KEEP THAT IN MIND WITH WHAT'S ABOUT TO HAPPEN NEXT, JUST KEEP YOUR FURRY LITTLE NOSE OUT OF MY PLANS AND YOU'LL BE HOME-FREE." The whirls of blue magic were summoned up again; and right before Bill/Sans teleported, "SEE YOU SOON!" was echoing through the entire house.

Meanwhile, a few moments later…

"Remember Papyrus, it's SUPPOSED to smell like burning!" Undyne instructed Papyrus as they proceeded with the cooking lesson.

"WELL, IT CERTAINLY DOES! WHICH IS WEIRD, CONSIDERING THE OVEN ISN'T EVEN ON YET…" Papyrus looked around the kitchen area curiously.

"What? I'm pretty sure that's not normal, even for MY house. Go see what's wrong, maybe it's just the fridge again…" Undyne walked to the other side of the kitchen.

Papyrus looked out one of the windows, after hearing what sounded like a scream. "AH, I'VE DISCOVERED THE PROBLEM! THERE SEEMS TO BE A LOT OF FIRE AND DESTRUCTION TAKING PLACE OUTSIDE AT THE MOMENT."

"What? What's going on!?" Undyne dashed to the nearest window, and she gasped. Weird creatures- that were nothing like the ones that had ever lived in the Underground- were all over the place, crawling and wreaking havoc.

"I never thought I'd really have to say this, but…we have to do something! It's time for us to fight, to defend everyone! That's what the royal guard is for!" Undyne practically jumped into her armor and grabbed her spear.

The Underground is usually so peaceful; it seemed like the only case where the Royal Guard would actually be needed is if a war broke out between humans and monsters again. Even after years of training and attacking humans, Undyne was scared. These creatures—whatever they may be—were nothing Undyne thought she'd ever need to fight. They weren't human; they weren't any type of monster she'd ever encounter before either.

And there was also the matter of Papyrus going into battle himself…he could fight, that was for sure. He probably could've even killed a human if he wanted to, but that was just the thing, he didn't want to. There was no way Papyrus could ever give an opponent anything less than a smile and some light-hearted attacks, he could easily get turned to dust out there.

"Papyrus!" Undyne called just before they went into battle, she didn't have time to explain why he should stay behind—but she did have the time and the power to watch out for him. "Don't let any of those freaks lay a finger and you, and don't hold back!"

"WORRY NOT, UNDYNE! THE GREAT PAPYRUS HAS BEEN TRAINING FOR THIS VERY DAY!" Papyrus opened the door; a blast of raging wind came bursting through. The two warriors looked at each other and nodded. Undyne flashed a threatening grin at the twisted creatures lumbering around, and Papyrus ran right beside her, fully prepared for any hell they would have to go through in order protect everyone.

The two of them were filled with DETERMINATION.