Kamen Rider × Kamen Rider Fourze & OOO: Movie War Mega Max (仮面ライダー×仮面ライダー フォーゼ＆オーズ MOVIE大戦 MEGA MAX Kamen Raidā × Kamen Raidā Fōze ando Ōzu: Mūbī Taisen Mega Makkusu) is the 2011 crossover film between Kamen Rider OOO and Kamen Rider Fourze in the same vein as the Movie War 2010 and Movie War Core. It features the casts of Kamen Rider Fourze and Kamen Rider OOO and aired in Japanese theaters on December 10, 2011. The catchphrase for the movie is "In Winter 2011, Movie War Will Evolve" (2011年冬、MOVIE大戦が〈進化〉する Nisenjūichinen Fuyu, Mūbī Taisen ga Shinka Suru).