In Unova's Survival Crisis!, when Ash's Pikachu freed Meloetta and sent the Team Rocket members flying with a powered-up Electro Ball caused by excess energy he absorbed from Thundurus earlier, Giovanni was struck by a beam of light from the Reveal Glass, causing him to become overwhelmed by its power and send the Legendary Pokémon on a rampage to destroy the region instead. Giovanni was eventually released from its possession when Jessie, James, and Meowth pushed him out of the spell circle he had been standing in. Following Team Rocket's subsequent retreat, Ridley used the Reveal Glass and Meloetta's song to calm down the rampaging Legendary Pokémon. Afterwards, the Reveal Glass was sealed away once again.
The Reveal Glass made its first proper appearance in Colress Machine, where it was shown to be in Colress's possession, using it to transform Thundurus and Landorus into their Therian Formes to fight Blake.
In Pokémon Legends: Arceus, the Reveal Glass is shown to have a handle, which it doesn't have in its other appearances. This implies that said handle breaks off at some point between the time of Legends: Arceus and the games taking place in the modern time.
Origin
The Reveal Glass may be based on the Demon Detecting Mirror, an item in Chinese mythology that could reflect the true identity of a yaoguai. Its design is based on the colors of Tornadus, Thundurus, and Landorus, with the Legends: Arceus design adding the colors of Enamorus.
