Armor Class 17 (natural armor)
Hit Points 157 (15d8 + 90)
Speed 40 ft.
Saving Throws DEX +8, CON +10
Skills Stealth +8
Damage Resistances acid, cold, fire, lightning, [object Object]
Damage Immunities poison
Condition Immunities charmed, frightened, poisoned
Senses darkvision 120 ft., passive Perception 10
Languages understands Abyssal but can't speak
Challenge 11
Amorphous. The alkilith can move through a space as narrow as 1 inch wide without squeezing.
False Appearance. While the alkilith is motionless, it is indistinguishable from an ordinary slime or fungus.
Foment Madness. Any creature that isn't a demon that starts its turn within 30 feet of the alkilith must succeed on a DC 18 Wisdom saving throw, or it hears a faint buzzing in its head for a moment and has disadvantage on its next attack roll, saving throw, or ability check. If the saving throw against Foment Madness fails by 5 or more, the creature is instead subjected to the confusion spell for 1 minute (no concentration required by the alkilith). While under the effect of that confusion, the creature is immune to Foment Madness.
Magic Resistance. The alkilith has advantage on saving throws against spells and other magical effects.
Multiattack. The alkilith makes three tentacle attacks.
Tentacle. Melee Weapon Attack: +8 to hit, reach 15 ft., one target. Hit: 18 (4d6 + 4) acid damage.
Mordenkainen's Tome of Foes, p. 130