In addition, a couple of subplots were added, one involving the legendary Pokémon Suicune, featured on the front cover of the game,[3] and the other involving the Unown. The game's biggest addition was the Battle Tower, a new building which allows players to participate in Pokémon Stadium-like fights.[2] The Japanese edition of the game was exclusively bundled with the Mobile Adapter GB,[lower-alpha 2] a device that allowed for connecting with other players via mobile phone.[4]