Once, when Sans repaired invention is located in his garage, he decided to find out what it is … and then …

He knew the true power of this device!
Clicking on the button, he called the gap of time and space!
Everything was erased from the face of the earth … and destroyed to zero …
Sans tried to fix it, but it did not work out.
Then he decided to reprogram the invention.
He struggled with it in silence and emptiness … and finally … he left!

Taking the car, he pulled the tighter the button that erased everything and all returned to their seats, but it’s not something imagined Sans, some monsters have merged into one, as “Amalgams”.

He decided not to take anything more than to anything else not to spoil. We lived still, as they have lived up to this incident. Yes, and no one remembered or knew about it, Sans still kept secret, but Frisk carried away his secret, was able to deduce from it the necessary information, and now she is trying to put everything back in its place …