Arcade games, and fighting games in particular, have a bit of a tradition when it comes to encountering super difficult bosses that can only be faced after meeting very specific conditions during the game’s campaign mode. Mortal Kombat had Reptile; the early Street Fighter games had Akuma; Real Bout Fatal Fury Special had Geese Howard. As of the latest update to Bandai Namco Entertainment’s Tekken-flavored Pokémon fighting game, Pokken Tournament is no exception to the rule.

Videos posted on YouTube and Niconico – Japan’s signature video hosting website – show a mysterious new entrant in the form of Dark Mewtwo, who seems to be an even more menacing version of the already-powerful Pokémon Mewtwo. The video below showcases a fight with Dark Mewtwo.

The conditions players must meet to fight Dark Mewtwo, however, have not been revealed.

Pokken Tournament is an upcoming arcade fighting game developed by Bandai Namco Entertainment and published by The Pokémon Company. It is the result of a brainstorming session between Tekken series producer Katsuhiro Harada and Soulcalibur producer Masaaki Hoshino, where they mused on different approaches to playing Nintendo’s classic role playing series. Pokken’s combat engine is loosely based off those belonging to Namco’s Tekken series, though the technical aspects of Tekken’s gameplay have been toned down to appeal to both casual and hardcore audiences. Players are represented as human Pokémon trainers, like those from the game’s home series, but control the Pokémon themselves and use a variety of abilities from the Pokémon series to defeat their opponents. The pre-release version of the game is currently only available for play in Japan, on select consoles and in select arcades.

Pokken Tournament is set to release in July 2016 in Japanese arcades, with a worldwide Wii U release arriving sometime during Q2 of 2016.