Stone-Eater Slime

Small ooze, unaligned

Armor Class 12 (natural armor)
Hit Points 90 (12d6 + 48)
Speed 20 ft., climb 10 ft.

16 (+3) 11 (+0) 19 (+4) 1 (–5) 6 (–2) 3 (–4)

Damage Immunities acid Condition Immunities blinded, charmed, deafened, exhaustion, frightened, petrified, prone
Senses blindsight 60 ft. (blind beyond this radius), passive Perception 8
Challenge 4 (1,100 XP)
Proficiency Bonus +2


  • Amorphous. The stone-eater slime can move through a space as narrow as 1 inch wide without squeezing.
  • Ooze Nature. The stone-eater slime doesn’t require sleep.
  • Spider Climb. The slime can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.


  • Multiattack. The stone-eater slime makes two Slam attacks.
  • Slam. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage plus 3 (1d6) acid damage. The target must succeed on a DC 14 Constitution saving throw or become petrified for 1 minute. A petrified creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
  • Dissolve Stone. The stone-eater slime touches a petrified creature or a nonmagical object or structure made of crystal or stone within 5 feet of it, ingesting some of the stone. If the object isn’t being worn or carried, the touch destroys a 6-inch cube of it, and the slime regains 10 (3d6) hp. If the object is being worn or carried by a creature, the creature can make a DC 14 Dexterity saving throw to avoid the slime’s touch. If the target is a petrified creature, it must make a DC 14 Constitution saving throw, taking 21 (6d6) acid damage on a failed save, or half as much damage on a successful one. Being petrified doesn’t give the creature resistance to this damage. The slime regains hp equal to half the damage taken. If the object touched is stone armor or a stone shield being worn or carried, it takes a permanent and cumulative –1 penalty to the AC it offers. Armor reduced to an AC of 10 or a shield that drops to a +0 bonus is destroyed. If the object touched is a held stone weapon, it takes a permanent and cumulative –1 penalty to damage rolls. If its penalty drops to –5, the weapon is destroyed.


This translucent orange blob scoots along a smooth stone floor, leaving pits and scores in the surface as it passes.

Stone-eater slimes burbled up from a pit of vitriolic acid earth elementals refer to as the Great Dissolution. They infest underground caverns and have migrated to many mountain ranges. Their paths often cross with mineral oozes, which they occasionally consume. Fortunate slimes encounter mineral oozes just as they’ve encased a meal, doubling the bounty for the slimes.

Hated by Medusas. Stone-eater slimes consume stone and favor petrified creatures and worked stone to all other forms of stone. They can petrify prey, but their petrification is unreliable, often ending before the slime has completed its meal. Thus, they lurk in the lairs of basilisks, medusas, and other creatures capable of petrifying prey. Less intelligent creatures, like basilisks, pay little attention to the slimes, as the creatures consume their stony meals too quickly for the slimes to have an appreciable impact. However, medusas and others who cultivate their petrified victims as statuary despise stone-eater slimes, who first mar and later completely destroy the perfect stone.

Incidental Hazards. Stone-eater slimes wear grooves and pits into the stone where they live. While the slimes keep away from heavily trafficked areas, they eventually do enough damage to less-frequented areas to create dangerous pit traps or weaken stone ceilings to produce deadfalls. Kobolds and other trap-savvy creatures entice stone-eater slimes into their lair, scattering worked stone in an area they want the slimes to excavate.

Section 15: Copyright Notice

Tome of Beasts 3 © 2022 Open Design LLC; Authors: Eytan Bernstein, Celeste Conowitch, Benjamin L. Eastman, Robert Fairbanks, Scott Gable, Basheer Ghouse, Richard Green, Jeremy Hochhalter, Jeff Lee, Christopher Lockey, Sarah Madsen, Ben Mcfarland, Jonathan Miley, Kelly Pawlik, Sebastian Rombach, Chelsea Steverson, Brian Suskind, Mike Welham

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