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Grimmlet Swarm

Size
Large
Type
Monstrosity
Challenge Rating
14
Source
Tome of Beasts 2
Alignment
Unaligned
Armor Class
15
Speeds
0, fly 30
Walking Speed
0
Flying Speed
30
Strength Score
17
Dexterity Score
12
Constitution Score
19
Intelligence Score
3
Wisdom Score
10
Charisma Score
18
Vision
Blindsight (120ft)
Languages Ref
understands Void Speech but can’t speak
Hit Points
152
Condition Immunities
Blinded, Charmed, Deafened, Frightened, Grappled, Paralyzed, Petrified, Poisoned, Prone, Restrained, Stunned
Resistances
Resistant to Bludgeoning Damage, Resistant to Piercing Damage, Resistant to Slashing Damage, Immune to Psychic Damage

Large monstrosity (Swarm), unaligned


Armor Class 15 (natural armor)

Hit Points 152 (16d10+64)

Speed 0 ft., fly 30 ft. (hover)


STR
17 (+3)
DEX
12 (+1)
CON
19 (+4)
INT
3 (−4)
WIS
10 (+0)
CHA
18 (+4)

Damage Resistances bludgeoning, piercing, slashing

Damage Immunities psychic

Condition Immunities blinded, charmed, deafened, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned

Senses blindsight 120 ft., passive Perception 10

Languages understands Void Speech but can’t speak

Challenge 14 (11,500 XP)

Enervating Maelstrom. When the grimmlet swarm dies, it explodes in a plume of ennui. Each creature within 20 feet of the grimmlet swarm must make a DC 17 Dexterity saving throw. On a failure, a creature takes 21 (6d6) psychic damage and suffers one level of exhaustion. On a success, a creature takes half the damage and doesn't suffer exhaustion. Grimmlets damaged by this trait don't Reproduce.

Maze of Edges. A creature that attempts to move out of or through the grimmlet swarm must succeed on a DC 15 Dexterity saving throw or take 9 (2d8) slashing damage.

Reproduce. When a grimmlet swarm takes damage from a spell and isn't reduced to 0 hp, a number of new grimmlets equal to the spell's level appear in unoccupied spaces within 10 feet of the grimmlet swarm. If the spell is a cantrip, only one grimmlet is created. New grimmlets aren't subsumed into the swarm. Sixteen or more new grimmlets within 30 feet of each other can use their reactions to come together and form a new grimmlet swarm in a space within 5 feet of one grimmlet.

Swarm. The grimmlet swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny grimmlet. The swarm can't regain hp or gain temporary hp.

Innate Spellcasting (Psionics). The grimmlet swarm's innate spellcasting ability is Charisma (spell save DC 17, +9 to hit with spell attacks). It can innately cast the following spells, requiring no components:
At will: maddening whispers, crushing curse, minor illusion
3/day each: hypnotic pattern, void strike, major image
1/day each: hallucinatory terrain

Actions

Multiattack. The grimmlet swarm makes two attacks with its crystal edges.

Crystal Edges. Melee Weapon Attack: +8 to hit, reach 0 ft., one creature in the swarm's space. Hit: 18 (4d8) slashing damage, or 9 (2d8) slashing damage if the swarm has half of its hp or fewer. The target must make a DC 17 Intelligence saving throw, taking 21 (6d6) psychic damage on a failed save, or half as much damage on a successful one.

Description

Flowing over the landscape like a glass carpet, this mass of smoky crystalline shards moves in a manner most unnatural. Occasionally, a bolt of black or purple energy arcs between two or more of the shards in the swarm._

Stat block from Tome of Beasts 2 (Kobold Press), Open Game Content used under the Open Game License 1.0a. Tome of Beasts 2. Copyright 2020 Open Design LLC; Authors Wolfgang Baur, Celeste Conowitch, Darrin Drader, James Introcaso, Philip Larwood, Jeff Lee, Kelly Pawlik, Brian Suskind, Mike Welham. It is not Geminaea material. See Legal.