Its so cool yet creepy at the same time

Underfell is the greatest AU known to man, that's what it is.

Yeah its cool but at the same time its... Unsettling

What's unsettling about reversing everyone's personalities?

Oh no! An opinion on the internet!

"The original is always the best." - GB-001
This is indeed true, since Underfell is the original AU and it's the best AU.

I disagree, but respect your opinion

...wow, first time I've said that quote and nobody's asked who said it.

Who said it?

An evil robot with a massive ego.

Searched on google and found nothing

Anyone with enough money can bribe search engines into omitting results.