During the Peloponnesian War, the snakes were the responsibility of the priest Doreios. Despite his attempts, some of the snakes escaped the tholos and a patient at the sanctuary was scared to death as he encountered them in the bath house. The Spartan misthios Kassandra was tasked to remove the snakes from the path, ideally forcing them to return to the tholos.
Behind the scenes
The model used for this specific tholos in Assassin's Creed: Odyssey shows it in the middle of construction, though a model for a whole tholos also exists in the game.