Armor Class 15 (natural armor)
Hit Points 172 (15d12 + 75)
Speed 30ft, swim 30ft
Saving Throws CON +8, STR +8
Skills Perception +6, Stealth +6
Damage Vulnerabilities fire
Senses Passive Perception 16, Tremorsense 60ft
Hold Breath The hydra can hold its breath for 1 hour.
Fire Vulnerability The laughing hydra is vulnerable to fire damage.
Multiple Heads The hydra has five heads. Each has 25 HP and can be targeted independently. Attacks targeting a head damage the head but not the hydra. If all its heads die, the hydra dies. If the hydra dies from damage not done to its heads, all the heads die. Each head saves independently against being blinded, charmed, deafened, and stunned.
At the end of its turn, any head that died this round grows two new heads in its place unless the head took fire damage this round.
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.
Patient Predator The laughing hydra spends long periods in near hibernation, its heads submerged under water but its huge, bulbous body near the surface. It can remain still for so long that reeds, grasses and other wetland vegetation will grow on its back, making it nearly indistinguishable from its surroundsings; a creature can make a DC 20 Wisdom (Perception) check to detect a hibernating hydra.
Multiattack The hydra 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.
Drowning Strike If a hydra’s head is hidden under water, it strikes out, attempting to grasp a creature in its jaws and pull it under. A large or smaller creature the hydra can sense within 10 feet must succeed on a DEX 15 saving throw or take 15 (2d10 + 5) piercing damage and be grappled. A grappled creature is pulled under water and begins to drown. On its turn, the creature can use its action to repeat the saving throw.
The Laughing Hydra gets one Legendary Action per round, which it may use to perform a drowning strike without being hidden.
Lair and Lair Actions
The Laughing Swamp On initiative count 20, all creatures must succeed on a DC 14 WIS saving throw or become incapacitated, falling prone and laughing uncontrollably for 1 minute. Each creature can repeat the saving throw at the end of its turn. A creature that succeeds its saving throw is immune from the effects for 1 hour.
While a creature is incapacited with laughter, at the start of its turn it must make a DC 14 Dexterity saving throw or roll into the water and begin to drown.
Each head of the hydra must also make save against the effects of the Laughing Swamp and succeeds or fails independently of the other heads. If the hydra drowns due to this effect on any one head, the hydra dies.
Dark Water The water of the Laughing Swamps is unnaturally dark and murky. Any creature totally submerged in the water has partial cover. If the creature is 5 feet from the surface, this increases to half cover. If the creature is 10 feet from the surface, it has total cover.Darkvision has no effect on visibility of submerged creatures.