Medium Plant, Chaotic Neutral
AC 15 Natural Armor    Initiative +1 (11)
HP 75 (10d8 + 30)
Speed 30 ft., Swim 30 ft.
Mod Save
STR 18 +4 +4
DEX 12 +1 +1
CON 16 +3 +5
Mod Save
INT 4 −3 −3
WIS 12 +1 +3
CHA 6 −2 −2
Skills Perception +3
Resistances Piercing and Slashing from nonmagical attacks
Immunities Acid, Lightning, Poison; Charmed, Frightened, Paralyzed, Poisoned
Senses Darkvision 60 ft.; Passive Perception 13
Languages Sylvan understands, but cannot speak
CR 4 (XP 1,100; PB +2)
Traits

Photosynthetic Hive The algoid is a colony of intelligent algae functioning as one creature. It can survive no longer than 3 days without sunlight; each 24 hours in darkness causes it to gain one level of exhaustion. If it dies from this exhaustion, its body blackens and decays rapidly.

Amphibious The algoid can breathe air and water.

Plant Empathy The algoid can telepathically command up to two nearby swamp or water-loving trees within 60 feet. Each tree acts on the algoid’s initiative and uses the Controlled Tree (see separate stat block in description).

Water Vulnerability The algoid takes 3 (1d6) damage per spell level from create or destroy water spells or effects.

Actions

Multiattack. The algoid makes two Slam attacks.

Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 8 (1d10 + 3) bludgeoning damage. On a hit of 19 or 20, the target must succeed on a DC 14 Constitution saving throw or be stunned until the end of its next turn.

Description

Algoids are colonies of intelligent green algae that have evolved into mobile, humanoid forms. Standing between 5 and 7 feet tall, their bodies shimmer with moisture and smell faintly of brackish water. Though seemingly primitive, their hive minds possess a strange empathy with water-loving trees, which they can animate to defend their territory.

They are often mistaken for trolls in dim light but are slower, calmer, and motivated more by instinct than malice. Left in darkness, algoids blacken and die, their cells starving without light. Some unscrupulous alchemists prize the remains of dead algoids for use in salves or gold purification.

Controlled Tree

Large Plant, unaligned

Armor Class 13 (natural armor)
Hit Points 45 (6d10 + 12)
Speed 15 ft.

STR 18 (+4) DEX 8 (−1) CON 14 (+2) INT 1 (−5) WIS 10 (+0) CHA 3 (−4)

Damage Immunities poison
Condition Immunities charmed, frightened, paralyzed, poisoned
Senses blindsight 30 ft. (blind beyond this radius)
Languages
Proficiency Bonus +2

Actions

Branch Slam. Melee Weapon Attack: +6 to hit, reach 10 ft., one target.
Hit: 7 (1d10 + 2) bludgeoning damage.

Variant: Purple Algoid

Medium Plant (Hive), Neutral

  • Habitat: Arctic coastlines, glacial waters.
  • Changes: Immune to cold damage; loses Plant Empathy but gains Crustacean Command (can psychically direct up to 10 Tiny sea creatures within 60 ft. to harass or distract foes).
  • Color Change: When deprived of light, turns fluorescent blue instead of black; powdered remains can dye cloth brilliant azure.

Previous Versions

Name Date Modified Views Adds Version Actions
1/30/2026 1:10:19 AM
4
1
1
Coming Soon
1/30/2026 1:15:16 AM
5
1
2
Coming Soon

Habitat: CoastalSwamp

kingvonkille

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