Sargassum Fiend

Large plant, unaligned

Armor Class 16 (natural armor)
Hit Points 136 (13d10+65)
Speed 20 ft., climb 20 ft., swim 40 ft.

25 (+7) 14 (+2) 20 (+5) 2 (–4) 11 (+0) 15 (+2)

Saving Throws Con +9, Str +11
Damage Resistances bludgeoning, cold, piercing
Skills Perception +8
Senses blindsight 60 ft., tremorsense 60 ft., passive Perception 18
Languages Deep Speech, telepathy 120 ft.
Challenge 9 (5,000 XP)

Special Traits

  • Mirage. A sargassum fiend emits a powerful scent that causes specific, miragelike hallucinations. All creatures within 300 feet of a sargassum fiend must make a DC 16 Wisdom saving throw or become charmed by the scent. A charmed creature sees the sargassum fiend as whatever would most compel it to approach. This might be a lost loved one, a child in need of help, an enchanting mermaid, the promise of dry land, and so on. This effect ends immediately if the sargassum fiend makes an attack against any target.
  • Water Breathing. The sargassum fiend can only breathe underwater.


  • Multiattack. The sargassum fiend makes two slam attacks.
  • Slam. Melee Weapon Attack: +7 to hit, 10 ft. reach, one target. Hit: 29 (4d10 + 7) bludgeoning damage. Instead of dealing damage, the sargassum fiend can grapple the target (escape DC 16).


A sargassum fiend is a free-floating mass of intelligent seaweed capable of luring its victims to their deaths via a powerful hallucinogenic pheromone. Once the sargassum fiend lures prey within striking distance, it grabs the entranced creature and attempts to crush it to death. Experienced sailors tell tales of entire crews jumping overboard to swim out to a murderous field of the sea plants. Sargassum fiends usually reach sizes up to 10 feet in diameter before splitting, their means of asexual reproduction. Mutations have been known to exist, however, and sea-faring scholars have recorded individual sargassum fiends reaching masses of truly enormous size.

Section 15: Copyright Notice

Sea Monsters (5E) © 2021, Legendary Games; Authors Michael Ritter, Michael “solomani” Mifsud, Robert J. Grady, Mark Hart, Jeff Ibach, Alex Riggs, Scott D. Young, Jeff Lee, Matt Kimmel, and Jason Nelson.

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