How to find boss?

[r0ssii]

Do you know which floor is correct for finding the boss? I am on a mission to kill him. I don't know if it's from a floor or it's an elevator ramdomizer.

[Prepostersauce]

I believe you have to be on floor 4 or lower (could be 5). You'll know the entrance to the fight when you see it.

[zaywd]

i know how to.
its in the deeper layers which means if you go far enough down in the elevator, like level 10 it will spawn the "event"

BETTER INFO:
i looked it up and it said if you go far enough down, You will most likely find the corrupted layers, which is IF YOU FIND MORE GRAIN ROT (rot) YOU ARE LIKELY TO FIND IT

break it down for y'all
more rot, more chances to find them,
I AM ON THE SAME QUEST LIKE YOU AND I HAVE BEEN STUCK ON IT