Watch Dragon Ball Z: The World's Strongest
Dragon Ball Z: The World's Strongest is an anime movie that was released in 1990. When Oolong and Gohan notice through the dragon radar that all the Dragon Balls are being collected, the evil Dr. Kochin calls upon Shenron, the eternal dragon. He wishes for Dr. Wheelo's lab to be released from the ice so he can get a body of the strongest fighter. Later Dr. Kochin and the Biomen appear at Kame House and demand Master Roshi but he refuses. He fights and easily defeats the Biomen, but at the same time kidnaps Bulma. She finds out Dr. Wheelo's plan and is told that Goku is the strongest. When Oolong tells Goku what happened, he goes to Dr. Wheeler's lab and rescue Bulma and Master Roshi.