Dragon Ball Z Movie 2: The World's Strongest

Synopsis:

Many years ago, Dr. Willow was said to have died, but before his death he implanted his brain into a robot body! Ever since, he's been on a quest to find the strongest man in the world to replace his robotic body. After years of searching, Willow's assistant finds Muten Roshi, former winner of the Tenkaichi Tournament and hailed master of martial arts. Suspecting Roshi to be the strongest man in the world, they capture him; but when Goku comes to rescue his master, Willow sets his evil sights on him as well...