Stohegeon, the Monolith Pokémon.
Evolves from Hengeon when a Hengeon is left in one of the cleared out circles in the forest and retrieved the next day.
This Rock/Psychic-type Pokemon is said to have been mistaken for a mysterious structure by explorers who stumbled upon a group of Stohegeon in their dormant state. They were barely able to escape when they accidentally awoke the group, which had been dormant for hundreds of years. When awakened, Stohegeon emerges as a towering monolith that stands watch over the forest. Its solid stone body is nearly impenetrable, and its psychic powers are said to be so strong that it can even levitate itself and nearby objects effortlessly. Despite its formidable appearance, Stohegeon is a peaceful creature that only uses its powers to protect the forest and its inhabitants.