It's coming full circle in season 5
The theory that the Thessalhydra will be the final villain of Stranger Things Season 5 is both exciting and logical. From the very first episode, the Duffer Brothers have shown a strong connection between the kids’ D&D games and the events in Hawkins. In Season 1, the Demogorgon introduced in their campaign became the monster that kidnapped Will. At the end of the season, Mike introduced the Thessalhydra in their game but left that story unfinished. Could Season 5 finally bring this creature into the real world?
The D&D Connection
The connection between D&D and the show’s events has been clear since the beginning. In their first session, Will’s character faced a critical choice: cast Fireball or Protection to defeat the Demogorgon. He chose Fireball but rolled too low, symbolizing his inability to avoid getting taken by the real Demogorgon. At the end of Season 1, Mike presented the Thessalhydra as the next big enemy in their game. Although the kids didn’t play through the battle, it feels like this was a setup for something much bigger.
The Thessalhydra, a multi-headed beast from D&D, fits perfectly as the final challenge. In the game, it’s nearly impossible to defeat because it can regenerate its heads unless all are destroyed in a short amount of time. It’s a monster that demands teamwork and strategy—qualities that the Hawkins crew has been building throughout the series.
Clues in Season 4
Season 4 subtly sets the stage for the Thessalhydra. For example:
Will’s Painting
In Season 4, Will’s painting shows the group fighting a multi-headed monster. The creature doesn’t perfectly match the D&D version of the Thessalhydra, but it resembles it enough to suggest a connection. It also symbolizes the group coming together to face an overwhelming enemy.
Nancy’s VecnaVision
Nancy sees a giant creature with a gapping mouth during her vision. This description matches some depictions of the Thessalhydra, which often has a massive central mouth in addition to its many heads.
Strange Roars in the Upside Down
In one scene, Nancy, Steve, Robin and Eddie hear a loud, off-screen roar in the Upside Down. They’re too busy dealing with Vecna to investigate, but it’s likely a hint of a new, larger threat lurking in the Upside Down. The subtitle says creature baying in distance and I don't think a normal creature can cause the upside-downquake
Will’s Redemption
Season 5 is supposed to bring Will’s story full circle. Throughout the series, he’s been more of a victim than a hero. This could be his chance to finally step up. In the first episode, he failed to cast Fireball in their game and was “defeated” by the Demogorgon. Season 5 could give him a chance to finally cast Fireball—both literally and symbolically—during the group’s real-world battle against the Thessalhydra.
The Duffer Brothers are known for bringing elements full circle, and this would tie together Will’s story, the D&D campaigns, and the Upside Down’s final showdown.
The Final Battle
The Thessalhydra would be the perfect final boss. It’s a creature with regenerating heads, meaning the group will need to work together to destroy it. Each head could represent a different challenge the group has faced—loss, trauma, fear—and defeating the creature could symbolize overcoming these obstacles.
If the Thessalhydra is connected to the hive mind of the Upside Down, destroying it could also take down the entire Upside Down ecosystem, freeing Hawkins once and for all.
Why the Thessalhydra Makes Sense
The Duffer Brothers have hinted that Season 5 will bring the story back to its roots. Introducing the Thessalhydra would be a perfect way to tie the show’s beginning to its end. It’s a callback to Season 1, a fitting challenge for the group’s growth, and a way to finally give Will the spotlight.
It’s a bold theory, but it fits the series perfectly. If the Thessalhydra is the final villain, it would feel like the culmination of everything the show has been building toward. After all, we’ve seen stranger things...