The next expansion set to the arcade game Pokémon Tretta has been announced. The Pokémon Tretta Set 1: Witness the Mega Evolutions (ザ・ポケモントレッタ 01弾 メガシンカをたいけんせよ) will feature the debut of Mega Evolved Pokémon and the use of the Pokémon Mega Ring. A red sparkly Master Tretta also makes it debut as does the Mega Evolve symbol on certain Tretta's.

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During battle, when the player receives damage, the "partner gauge" will fill up. When it reaches "MAX", the player will be able to Mega Evolve. Players can then use their Pokémon Mega Ring to evolve the Pokémon. Players do not need to have the Mega Ring bracelet to Mega Evolve in the game as they can borrow a Key Stone from the Pokémon Tretta League by selecting the Mega Evolve symbol on the selection wheel.

Source: http://www.pokemontretta.com/tretta/t10/index.html