Toxic Ooze is one of the three kinds of pit hazard, alongside water and Spikes.
It appears in the rooms of Slime Pits, where it sits alongside the floor and wall spikes and the inner wall structures that limit a room's usable space.
Toxic Ooze is a floor hazard rather than a trail left by an enemy. For the trails that slime enemies leave behind, see Goo trail.
Compiled from what this wiki already says on Rooms, Slime Pits. No new facts were added.