Cramorant

Flyby. Cramorant doesn’t provoke opportunity attacks when it flies out of an enemy’s reach.

Dive (2-turn Action).
On its turn, Cramorant dives beneath the water and vanishes. It becomes heavily obscured, cannot be targeted, and gains resistance to all damage until the start of its next turn.
On its next turn, Cramorant emerges beneath a creature within 40 feet and makes a special melee attack:
+6 to hit, 5 ft. range. Hit: 22 (5d6 + 2) bludgeoning damage.

Drill Peck. Melee Weapon Attack: +5 to hit, reach 5 ft., one target.
Hit: 10 (2d6 + 3) piercing damage.

Hydro Pump (Recharge 4–6).
Cramorant exhales a blast of compressed water in a 30-foot line that is 5 feet wide. Each creature in the line must make a DC 14 Dexterity saving throw, taking 21 (6d6) cold damage on a failed save, or half as much on a success.

Brave bird.
Cramorant dives from the air into a target directly below. It moves up to 30 feet straight down and makes a special melee attack. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 18 (4d6 + 3) bludgeoning damage. Cramorant then takes 2d6 + 3 bludgeoning. If Cramorant moved at least 20 feet before attacking, the target must succeed on a DC 14 Strength saving throw or be knocked prone. 

Gulp Missile (Recharge 5–6).
After Cramorant has used Dive within the last hour, when Cramorant is hit by a melee attack, it can use its reaction to unleash whatever it's holding in its beak. Roll a d4:

• 1–2: Fish Missile – The attacker takes 2d8 piercing damage.

• 3–4: Pikachu Surprise – The attacker takes 2d6 lightning damage and must succeed on a DC 14 Constitution saving throw or be stunned until the start of their next turn.