THE FIELD GUIDE / GUIDE
The Giant Slime in Deep Dish Dungeon
The Giant Slime is a moving sewer obstacle: wait for it to pass or go around it, because touching it causes damage.
Find and recognize it
The Giant Slime wanders in part of the sewer. In a published test, 山丸にき reports that it did not pursue the player but did damage on contact. Watch its movement before entering the narrow passage.
Patch 1.0.50.0 raised the water level in the Giant Slime corridor and moved objects to provide new routes around it. Older directions may describe a different layout.
How to get past
Wait until the slime has moved past you, then continue through. Forcing your way through is possible in the cited player account, but contact causes damage.
The same author reports trying swords, arrows, Pickaxe, Axe, Hammer and explosives without damaging the slime. That is a bounded test, not proof that every possible attack can never work.
Slime versus goo piles
A goo pile is the material blocking some passages; players break it with a Pickaxe and can obtain Clay. The Giant Slime moves through a sewer corridor and should be avoided or passed. These are different obstacles; the cited accounts do not establish that one creates the other.
Water near the corridor
A separate walkthrough identifies a valve above a ladder reached from the stairs near the Harpoon chest; it drains water in the slime area. This is a water-control landmark, not a claim that turning it kills the slime.