Algaec

False Appearance. While the Algaec remains still, it is indistinguishable from a cluster of briny seaweed & algae.

Magic Resistance. The Algaec has an advantage on saving throws against spells & other magical effects.

Creature of the Sea. Has a disadvantage on Perception checks in sunlight, a result of a life spent in the deep-sea reefs & seaweed forests.

Multiattack. The treant makes two Slam attacks.

Slam. Melee Attack Roll: +9, reach 5 ft. Hit: 16 (2d6 + 4) Piercing damage. A creature makes a Con Save Dc 14 or be Poisoned & takes [roll]3d6+3[/roll] Poison damage on a fail. 

Algae Bloom (Recharge on 5-6). Racial ability. The Algaec releases a bloom of algae & seaweed polyps into a thick cloud in water and air. In air - radius 20ft. In water - radius 50ft. Any creature caught in the bloom makes a Con save. On a fail, a creature is poisoned and takes [roll]3d8+3[/roll] poison damage & is restrained by the sludge of algae & polyps. A creature takes half damage and is not restrained or poisoned.

Breath of Brine. The Algaec exhales a breath of noxious, steaming brine in a 30ft cone. A creature makes a DC 16 Con save or takes [roll]6d8+6[/roll] Necrotic Damage, & half on a save. The Algaec will heal for half of the damage rolled against the creatures, not a cumulative effect.

Bloated Defense.  When a creature attacks the Algaec with a melee attack, it can use its reaction to thicken the seaweed & algae of its body, raising its Ac by 2 for the remainder of the round.

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