Gray ooze

A gray ooze resembles a thick puddle of gray sludge, roughly 8" (20 cm) and up to 14' (4.27 m) across, that closely resembles wet stone or an amorphous rock formation. They are mindless scavengers who drag themselves around caves and sewers and absorb and digest whatever they come across. Unlike other oozes, the gray variety cannot move on ceilings or walls, hence it is left to slide its way along subterranean floors. Gray oozes reproduce by breaking small driplets off of them after a meal, which later grow into gray oozes themselves.

While possessing an immunity to magic, fire and cold the gray ooze cannot speak. They attack by striking until its prey is either dead or unconscious, moving on top of them afterwards to digest them from within. Acidic secretions of the gray ooze corrode metal at an alarming rate; as a result, blacksmiths also sometimes use jarred gray oozes to meld ore into the right shape.