Multiattack

Two Tentacle Lashes and one Stinging Tentacle.

Tentacle Lash

Melee Weapon Attack: +8 to hit, 15 ft., one target, 14 (3d6+4) bludgeoning damage.

Stinging Tentacle

Melee Weapon Attack: +8 to hit, 15 ft., one target, 7 (1d6+4) piercing damage + 9 (2d8) poison. Target must make DC 16 Con save or be paralyzed for 1 min. A frightened creature has disadvantage on this save. Paralyzed target can re-save at end of each of its turns success ends effect on itself.

Frightening Visage (Recharge 5-6)

If underwater it flares the light from its organs making skull-like structure within more apparent. If above water the coastline reaper tightly pulls in its outer flesh causing its body to take on a fleshy skull-like appearance. Each Humanoid within 30' of it that can see it: 21 (6d6) psychic and frightened 1 min (DC 16 Wis half not frightened). Frightened creature can re-save at end of each of its turns success ends effect on itself.