>>52416408Back in April, PokeMiners identified that Groudon, Kyogre, and Rayquaza would have a 300 energy cost, along with Latias, Latios, Gyarados, Altaria, and the not yet released Mewtwo, Tyranitar, Garchomp, Metagross, Diancie.
https://twitter.com/poke_miners/status/1519772957329051653This was back when Niantic overhauled the mega evolution mechanics and made them worth a damn.