Bearcarp

Amphibious. The bearcarp can breathe air and water.

Blood Frenzy. The bearcarp has advantage on melee attack rolls against any creature that doesn't have all its hit points.

Charge. If the bearcarp moves at least 20 feet straight toward a target and then hits it with a melee attack on the same turn, the target takes an extra 18 (3d8+5) damage. If the target is a creature, it must succeed on a DC 18 Strength saving throw or be knocked prone.

Frightful Presence. Each creature of the bearcarp's choice that is within 5 feet of the bearcarp and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the bearcarp's Frightful Presence for the next 24 hours.

Keen Sight and Smell. The bearcarp has advantage on Wisdom (Perception) checks that rely on sight or smell.

Regeneration. The bearcarp regains 10 hit points at the start of its turn if it has at least 1 hit point.

Multiattack. The bearcarp makes two attacks: one with its bite and one with its claws.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 10 (1d10 + 5) piercing damage.

Claws. 14 Attack: +7 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) slashing damage.