What do you get when a wizard combines a snapping turtle, an octopus, a moray eel, a hydra, and a dash of demonic corruption?
Before his home was consumed by the Merak, the eccentric wizard Jah-Aims specialized in creating exotic pets for the wealthy. Utilizing ancient “combination cubes,” he produced wonders like the winged cat and flops like the scorpion squirrel. But when war escalated, the factions demanded weaponized horrors.
Influenced by the succubus Kullina, who secretly introduced chaotic demonic elements into his experiments, Jah-Aims set out to create the ultimate amphibious engine of terror. By fusing the eggs of a snapping turtle, octopus, moray eel, and hydra, he forged the Chelonian Hydra.
Though Jah-Aims was eventually slain and his laboratory buried, his dormant masterpiece survived. Now, after decades of slumber, the Chelonian Hydra has awakened—and its insatiable hunger has driven it to hunt once more.
What’s Inside?
The Chelonian Hydra (CR 12): This Huge monstrosity features:
- Turtle Powered Defense: A rock-solid AC 19 natural armor shell.
- Five Moray-Eel Heads: Capable of devastating venomous bite attacks.
- Grappling Tentacles: Tentacles that can grapple and restrain up to four targets simultaneously.
- Ranged Bone Spines: Demonic projectiles that allow the hydra to kill targets from afar.
- Acidic Volley: A recharging 30-foot cone spit attack that melts flesh and armor alike.
- Regeneration: Cut off one head, and two more grow back!
Four Battle Maps: Ready-to-use combat maps offering diverse battlegrounds.
- Building Map: A farmstead setting for a terrifying land assault.
- Beach Map: Perfect for a coastal clash (complete with a dock).
- Sea Bottom Map: For deep-sea, underwater confrontations.
- Shipwreck Map: Fight amidst the sunken ruins of a merchant vessel destroyed by the beast.
Can your players shatter the shell or will they become the next meal of the Chelonian Hydra?
Mike’s Free Encounter #130: Chelonian Hydra – Dungeon Masters Guild | Dungeon Masters Guild
Videos for my D&D products are available on my Eternal Library: Random Universes YouTube channel.
Information about my other D&D products is available on my web site, drmcl.com and my free to subscribe Random Universes: Eternal Library substack:

Enter the Temple of Bones and challenge the undead hierophant!
Infiltrate the venom cult’s desert stronghold and stop a deadly new threat before it strikes!
The show must go on.
The Widow’s Game moves to the Cold Land. The sentient crossbow Widow’s Kiss has called forth a new challenge: Heleka, a frost giant who hunts the deadly rhemorhaz.
Widow’s Kiss’ Challenge is heating up. The sentient hand crossbow continues its deadly game of seeking the ultimate predator to wield it. This time, the call of the weapon has reached deep into the heart of cursed dwarven city.
The Widow’s challenge has begun. The legendary hand crossbow, Widow’s Kiss, is whispering in the dreams of the most dangerous archers, seeking a new wielder. This sentient weapon—crafted from phase spider chitin and woven shadow—seeks a fellow predator devoid of kindness to claim it through a series of lethal challenges of the Widow’s Game.
Mundurin Ironshaper has a dream: to restore his family’s legacy by retrieving the machine needed to forge the legendary Dwarven Iron Donkeys—mechanical marvels infused with elemental fire spirits. But the means of their creation lies deep within the mountain fortress of Baraz-Khadur, a city lost to the ancient red dragon V’Shelexa the Maker of Ash.
ill you rescue the missing party, or be double devil-donked to death?
This is the 121st in an ongoing series aimed at providing the overworked DM with ready-to-run encounters.