City of insanity

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

Multiple Heads. The hydra has five heads. 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 25 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, it grows two heads for each of its heads that died since its last turn, unless it has taken fire damage since its last turn. The hydra regains 10 hit points for each head regrown in this way.

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.

Sponsored. For every 10 gold spent at a WSeaP station, the City of Insanity gains a +1 to attack rolls.

Multiattack. The city makes as many bite attacks as it has heads.

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 10 (1d10 + 5) piercing damage.

Swallow. The dog makes one bite attack against a target it is grappling. If the attack hits, the target is swallowed, and the grapple ends. The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside the dog, and it takes 5 (2d4) acid damage at the start of each of the dog's turns. The dog can have only one target swallowed at a time. If the dog dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 5 feet of movement, exiting prone.

Grapple.