Mind flayer
From A KoL Wiki

This is a mind flayer, not to be confused with a mime fileter. This thing flays minds, and that other thing probably cuts mimes into steaks. Good riddance. Dumb mimes.
He starts to flay your mind, but gets distracted by all the weird stuff you remember.
He tries to flay your mind, then realizes minds don't have skin.
You hit for 49 damage.
You win the fight!
You acquire an item: mind flayer corpse
You gain 3 Fortitude.
You gain 3 Wizardliness.
You gain 2 Smarm.
Occurs in the Dungeons of Doom.