Gray ooze

A gray ooze was a type of ooze.

Description
It was a thick puddle of gray sludge, roughly thick,  wide, and up to  across, that closely resembled wet stone or an amorphous rock formation.

Behavior
When one of these creatures reached an exceptionally large they were known to mildly develop greater intellect.

Biology
These creatures could corrode metal at a rate comparable to that of a black pudding, though its acids could not eat through stone or wood.

Gray oozes reproduced by breaking small droplets off of them after a meal, which later grew into gray oozes themselves.

Abilities
Gray oozes possessed an innate immunity to magic, as well as severe heat and cold. However, they were vulnerable any form of lightning.

When one of these creatures reached an exceptionally large they would develop latent psionics, allowing them to unleash a psychic crush, but in return be left vulnerable to retaliation. They were only known to unleash this ability whenever a creature within of them used psionic powers.

Combat
It attacked by striking until its prey was either dead or unconscious, moving on top of them afterwards to digest them from within. Acidic secretions of the gray ooze corroded metal at an alarming rate; as a result, blacksmiths also sometimes used jarred gray oozes to meld ore into the right shape. Gray oozes were particularly feared for the fact that they were transparent. This made them difficult to detect while they were still or moving slowly.

Habitats
Gray oozes were known to be found in cold swamps and marshes, as well as caverns and dungeons. They were mindless scavengers who dragged themselves around caves or sewers, while absorbing and digesting whatever they came across. Unlike other oozes, the gray variety couldn't move on ceilings or walls, hence it was left to slide its way along subterranean floors.

Appearances

 * Adventures:
 * Dungeon #30 ... And a Dozen Eggs • Curse of Strahd • Waterdeep: Dragon Heist • Waterdeep: Dungeon of the Mad Mage
 * Gamebooks
 * Escape the Underdark
 * Video games
 * Baldur's Gate II: Shadows of Amn • Neverwinter Nights: Darkness over Daggerford
 * Organized Play & Licensed Adventures
 * Curse of Strahd • Out of the Abyss
 * Card Games
 * Sword Mountains Crypt