Sea Serpent A5E

Melee Weapon Attack: +14 to hit, reach 5 ft., one Large or larger target in its space. Hit: 51 (4d20 + 9) bludgeoning damage. If the target is a creature it is grappled (escape DC 22). If the target is an object it is held. Until the grapple or hold ends the targets speed is reduced to 0 and the sea serpents coils attack automatically hits the target. If an attacker subjects the serpent to a critical hit this grapple or hold ends.

The serpent moves up to its speed and then attacks with its tail and its bite.

Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 27 (4d8 + 9) bludgeoning damage. If the target is a creature it makes a DC 22 Strength saving throw. On a failure it is pushed up to 15 feet away from the serpent and knocked prone.

Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 31 (4d10 + 9) piercing damage.

The serpent ends one condition or effect on itself.

If the serpent takes 15 damage or more from a melee attack made by a creature it can see, it bites the attacker.

If the serpent takes 15 damage or more from an attack made by a creature or object it can see, it makes a tail attack against the attacker.