Hunt for the Thessalhydra is a short adventure published by Wizards of the Coast as a tie in to the "Stranger Things" franchise and part of the Stranger Things Dungeons & Dragons Starter Set. The adventure features characters, locations, and monsters inspired by that series. The adventure is suitable for characters of level 3-5.

When the priestess of Ehlonna was murdered by a werewolf, the townsfolk of Deepwood lost no time in meting out justice, even though the shapechanger turned out to be a trusted friend and neighbor. But his journal has the town worried. Written in an unknown tongue, it seems to contain important pieces of information. Is it a list of other werewolves? Is the threat to Deepwood over, or has it only just begun? Cries of "Murder!" brought the villagers of Deepwood running to the temple to witness a grisly sight. The priestess of the Temple of Ehlonna lay murdered on the floor, savaged by some vicious beast. Above her body stood a large wolf. Then, before their horrified eyes, the wolf turned into a man -- their friend and neighbor Trammil! The villagers lost no time in giving Trammil the justice he deserved at the end of a rope, even over the objections of those few who thought he deserved a trial. But Trammil's death has not made the villagers feel safe. No one suspected his dark secret until the day of the crime. Could there be others? Can anyone in town be trusted? Only someone who can translate Trammil's journal and fully investigate the murder can solve the mystery.