Humans knew about the monsters that lived in Mt. Ebbot. Well, some of them did. Scientists made love with fanatics and bred a group of mental patients who were hellbent on getting down there alive. They couldn't drill into the mountain, they couldn't break the barrier, so they tried their next best bet. Teleportation.

You were one of their dozen subjects testing the technology. Many before you had died or became mutated in the process. Horrors beyond rationale and all that. But they believed they'd come to a final product.

They drove you out to the base of the mountain with their crazy device, strapping you into it as you fought against them all while someone in the back punched in a bunch of numbers you had no hope of understanding. A button was pressed, and you were dismantled at an atomic level. Just as you had been time and time before.

It worked.

And something went wrong.

You rematerialized on snow. Cold snow. Biting snow. You'd push yourself out of it if you could feel your body. It's all numb and staticy. The... Body that doesn't feel like yours. This body isn't yours. You aren't human anymore, this isn't right. You aren't you anymore.

The only thing that's louder than the ringing in your head is the hushed whispers of nearby monsters. Frogs, lizards, dogs and cats and a bird or two, even some things that look like ghosts or... Just unreal creatures, all muttering frantically.

Boots suddenly crunch against snow, rapidly growing louder as whoever holds them approaches. It's quickly followed by a much lighter, softer trail of a second being. One calls out to the other in a high pitched panic,

"Sans! Sans, w-who is this?? This isn't a resident, i-is it someone's child? They fell from the sky, Sans, We don't have a sky! S-should I call Undyne?!"

A second character replies in a calmer, but still clearly deeper and slightly shaken voice,

"Paps, clam down. It's... Just a new monster. Call Undyne if you want, but we probably just haven't... Seen them before."