Kinnikuman: Gyakushuu! Uchuu Kakure Choujin
Japanese title: キン肉マン 逆襲！宇宙かくれ超人
Type: Movie
Episodes: 1
Source: Manga
Genres: Comedy, Sports
Studios: Toei Animation
Duration: 38 min
Rating: PG-13 - Teens 13 or older

As the whole world watches the Choujin Rugby game on TV, the "Underground Space Emperor" Hydra King has his Underground Space Supermen kidnap Robin Mask. Their aim is to lure out the Seigi Choujins and then attack them using the Robin Memo, which contains info on all of the Seigi Choujin's weaknesses. Watching on TV all over the world, Kinnikuman and the Seigi Choujins get together and head for Planet Hydra.

(Source: Kinnikuman Wiki)