The laughing hydra is a fey reptilian horror with a crocodilian body and multiple heads on long, serpentine necks. Although its heads can be severed, the hydra magically regrows them in short order.
Lover of Jokes The Laughing Swamp is a vast bog summerwise in the Feywild, in which swarms of insects constantly tell each other bad jokes; any unfortunate creature that ventures too close to the swamp risks becoming incapacitated by magical laughter, losing their footing and disappearing into the depths of the black waters and laughing as they drown.
The laughing hydra is just smart enough to understand a few of these jokes, making it susceptible to the swamp’s strange effects. For this reason it spends most of its time in near hibernation submerged in the murky depths below the surface and only raising a head occasionally to breathe. Loud laughter will attract the hydra’s attention, both as a possible source of easy prey and a good chuckle.
When a hydra sleeps, at least one of its heads remains awake and alert, making the creature difficult to catch by surprise.