The Ultimate Challenge
After defeating Eskara The Kid is summoned back to Muscle Planet to test his Ultimate Muscle power! He is weak and is bruised from his battles and so is given the chance to fight the Gruesome Threesome (a group of wrestlers who got there name from what their victims looked like) to find alternative ways to win otherthen getting beaten up. But his Muscular foes won't be easy to overcome.
Aired 21/08/2002EP 33 - The Ultimate Challenge
Ultimate Muscle
Kid Muscle (or Mantaro for short) is a bumbling, gross, and wimpy sort-of person. Unfortunately, he has been summoned to protect the earth from the evil dMp, a band of cheating wrestlers from outer space. Luckily he's not undertaking this task alone. Kid Muscle must join the Muscle League, a group of wrestlers from outer space who are training themselves so they can defend the earth, and stop the dMp by achieving "Ultimate Muscle", a hidden power that makes Mantaro an almost unbeatable opponent.
(Source: Anime News Network)