hey guys just asking I forgot what mode it is when you go up to the surface with all of the monsters?

No mercy route.
I'm kidding, you have to do the True Pacifist or Pacifist Route.

Sorry but i didnt know Undertale i try to have the game. Or i licten youtuber play it for know.

Pasafist

Don't kill anything and go on a date with papyrus (or hang out), make friends with Undyne, Hang out with Alphys and discover her dark secret and deliver a letter to Alphys from Undyne. This will get you to the pacifist ending, I hope this helped!

Don't kill anything, even Papyrus or Sans will kill you.

ty guys really helped

you mean the pacifist path?