Five months from now, the skies above Hawkins will tear open one last time. The fate of Stranger Things hangs in the balance, resting on the weary shoulders of its young heroes. Since the Tudum reveal unleashed the endgame date, the fandom has stirred like a hive, breathing life into theories, dread, and long-dormant nightmares. As darkness creeps back into Hawkins, slick with nostalgia and something far more sinister, whispers of an ancient horror—Thessalhydra—slithers into the cracks of season 5 speculations.

Vecna, the Mindflayer, and Demogorgons are monsters fans have tangoed with before. But who, or what, is Thessalhydra? And why does it feel like the Upside Down is not done feeding yet?

About Thessalhydra, the monstrous entity that can make Stranger Things stranger than ever

According to Hawkins Happenings on X, Stranger Things season 5 is rumored to introduce a new monster with eight legs and a gaping mouth, resembling the Mind Flayer, but not quite the same. It is reportedly the same size as Meatflayer from the third season, and tate.brookins on X suggests the entity could be Thessalhydra. Thessalhydra is a fictional creature from Dungeons & Dragons, originally published in the second edition of the Monster Manual, published in 1983, and described as a reptilian monster with eight hydra-like heads and a large, gaping mouth. 

The rumored introduction of Thessalhydra in season 5 is not a recent development. One of the most intriguing season 1 details, conjoined with Nancy’s visions in the fourth installment, suggests the possibility of Thessalhydra’s sinister arrival in Stranger Things. In the last season, when Nancy recounts what Vecna’s vision showed her, she mentions a “giant creature with a gaping mouth,” akin to the descriptions teased by the scoopers fanning the flames of Thessalhydra.

In reality, though, the reference to Thessalhydra dates back to season 1.

Where was Thessalhydra shown in Stranger Things season 1?

According to the Dungeons & Dragons lore, Thessalhydra is an 8-head monster with a gaping mouth, which fits eerily to Nancy Wheeler’s description of the creature she sees in her vision in Stranger Things season 4. While people might let it slide as a mere presumption, Will’s painting of Mike and the Hawkins gang fighting a creature with several heads serves as a clue hard to overlook in season 4 volume 2. On top of that, in season one, Will, Mike, Dustin, and Lucas play D&D in the Wheelers’ basement.

In the scene, the monster Mike drops on the board is the Thessalhydra. In the game, the campaign was won, but in reality? Not yet. Considering the Duffer Brothers have already teased a full circle for Stranger Things with season 5, this link between season 1 and Nancy’s visions in season 4 most likely ties to Thessalhydra. Of course, only time will reveal whether the guesses are on point. But so far, every enigmatic clue points at this 8-headed monster, who is about to make Stranger Things 5 a must-watch.

Do you think Thessalhydra is the ultimate villain of Stranger Things season 5? Let us know in the comments below!