Multiattack

The shellycoat makes one Bite attack and one Claw attack.

Bite

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage.

Claw

Melee Weapon Attack: +5 to hit, reach 15 ft., one target. Hit: 12 (2d8 + 3) slashing damage, and the target is grappled (escape DC 13) if it is a Large or smaller creature. Until this grapple ends, the creature is restrained. The shellycoat has two claws, each of which can grapple only one creature.

Shellycoat's Fog (1/Day)

While in contact with water, the shellycoat can create a 20-foot-radius sphere of fog centered on a point it can see within 60 feet of it for 1 minute. The sphere spreads around corners, and its area is heavily obscured. A creature that enters the fog for the first time on a turn or starts its turn there must succeed on a DC 13 Constitution saving throw or be poisoned and unable to breathe, unless it can breathe water, for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.