Marfish Ray

Amphibious forms. The Marfish can use a bonus action to turn into a goldfish or return to its original form.

While a goldfish, the Marfish retains its current hit points and regains 30 hit points at the start of its turn if it has at least 1 hit point and is submerged in at least 5 inches of water.  In addition it is immune to all bludgeoning damage. The goldfish has a swim speed of 30ft, and a walk speed of 5ft. The goldfish can use its action to disengage, dash or make a bite attack (+3 to hit, 1 piercing damage).

Multiattack. The Marfish makes three attacks: one slam and two punches.

Slam. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 15 (2d10 + 4) bludgeoning damage. The target must succeed on a DC 10 Strength saving throw or be knocked prone.

Punch. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage.

Confusing Speech (Recharge 5-6). The Marfish shouts poorly phrased instructions, and  obscenities in a 60ft cone. Creatures within the cone must make a DC 15 Wisdom saving throw. Affected creatures take 25 (6d6+4) psychic damage and are under the effect of confusion, on success creatures take half damage and resist the confusion. Creatures repeat the save against the confusion at the end of each of their turns.