Alchemic Hydra

Hold Breath. The hydra can hold its breath for 1 hour.

Multiple Heads. The hydra has five heads. Each head matches one particular type of beast. While it has more than one head, the hydra has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

Whenever the hydra takes 30 or more damage in a single turn, one of its heads dies. If all its heads die, the hydra dies.

At the end of its turn, the hydra regains 15 hit points, unless it has taken fire damage since its last turn.

Reactive Heads. For each head the hydra has beyond one, it gets an extra reaction that can be used only for opportunity attacks.

Wakeful. While the hydra sleeps, at least one of its heads is awake.

Multiattack. The Alchemic Hydra makes a number of attacks based on how many heads it has. It makes 3 attacks if it has 4 heads, 2 attacks if it has 3 heads, and 1 attack if it has 2 or less heads, not including the dragon head.

Cobra. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 1d8+5 piercing damage, and the target must make a DC 16 Constitution saving throw or take an additional 1d6 poison damage.

Falcon. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 1d6+5 slashing damage, and the target is grappled (escape DC 15). While the target is grappled, this head cannot be used to attack.

Goat. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 2d6+5 bludgeoning damage, and be knocked 5 ft. back.

Wolf. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 1d10+5 piercing damage, and the target must make a DC 16 Strength saving throw or be knocked prone.

Dragon (Recharge 5-6). The dragon exhales fire in a 30-foot cone. Each creature in that area must make a DC 16 Dexterity saving throw, taking 10d6 acid damage on a failed save, or half as much damage on a successful one.