Kelpie (5e Creature)
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Medium plant, chaotic evil
Saving Throws Con +3, Cha +4
Changing Appearance. The kelpie can use its action to alter its form to resemble a green-clad woman, a sea horse, or a green horse, or back into its true form, which is a plant.
Seaweed Creature. Kelpies can walk around on land, but they take 10 (3d6) necrotic damage for every hour they are out of water.
Power Immunity. Female creatures are immune to the kelpie's Changing Appearance and charm person spell.
Innate Spellcasting. The kelpie's innate spellcasting ability is Charisma (spell save DC 12). The kelpie can innately cast the following spells, requiring no components:
Wrap. Melee Weapon Attack: +4 to hit, reach 10 ft., one target. Hit: 6 (1d6 + 3) bludgeoning damage and the target becomes grappled (escape DC 12).
Crush. Melee Weapon Attack: +4 to hit, reach 0 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage.
The kelpie is a mass of animated seaweed that is able to change its form at will. It lives to drown the foolish, and usually target humanoid males to devour. Males who are led into believing the kelpie is a woman not near water are led to the suitable location near the kelpie's home. If a humanoid is found near their lair, the kelpie only has to convince the male to come into the water and embrace the kelpie. Afterwards, the kelpie wraps itself around the charmed victim while dragging them underwater.