Dragon Ball Z: The World’s Strongest

Dr. Wheelo's original body was destroyed in an avalanche fifty years ago. His brain was kept alive by advanced technology inside his lab, but he was trapped in the ice. After being revived through the Dragon Balls, he seeks the body of Earth's strongest warrior to become his new host, allowing him to live again in a physical form.

The film opens with Dr. Kochin revealing Wheelo's frozen state and his desire to find a suitable body.

Dr. Wheelo believes Master Roshi is Earth's strongest warrior based on historical records and information available to Dr. Kochin. This is why he sends his bio-men to kidnap Bulma as leverage to force Roshi to come to the lab.

Dr. Kochin specifically mentions Roshi as the target when discussing the plan with Wheelo.

Wheelo witnesses Gohan's power when the boy's anger causes him to shatter Wheelo's brainwashing device that was controlling Piccolo. This display of hidden strength makes Wheelo decide that Gohan's body would be far superior to Roshi's.

Gohan's unexpected power surge when trying to stop brainwashed Piccolo directly catches Wheelo's attention.

When brainwashed Piccolo attacks Goku, Gohan tries to stop him but fails. This triggers a furious outburst of Gohan's latent power, which shatters Wheelo's brainwashing device. The sudden burst of energy breaks the control and frees Piccolo.

Earlier scenes establish that Gohan possesses hidden power he cannot fully control.

Once Wheelo breaks free from his robot body to fight directly, Kochin becomes a liability. When Wheelo smashes through the ice wall, Kochin falls down a shaft to his death. Wheelo no longer needs Kochin since he can now pursue a body directly on his own.

Wheelo shows willingness to discard anyone who stands in his way, including his former minions.

Goku begins forming a Spirit Bomb, but Wheelo interrupts him. The Z-Fighters distract Wheelo long enough for Goku to complete the attack. The massive energy blast hits Wheelo directly, destroying him completely.

Goku uses the Spirit Bomb technique against powerful enemies throughout the series.

Dr. Kochin kidnaps Bulma and uses her as leverage, knowing Roshi would not let her die. Roshi defeated the initial bio-men but realizes he must follow them to rescue Bulma, even though he suspects it's a trap.

Roshi's protective nature toward his friends is established early in the film.

Dr. Wheelo created three bio-warriors (Mikokatsun, Kishime, and Ebifury) as his main fighting force to capture potential body hosts and eliminate threats. They serve as guards for the lab and test the strength of potential warriors like Roshi and Goku.

The bio-warriors are revealed as Wheelo's primary weapons when they overwhelm Piccolo early on.

Dr. Wheelo uses his brainwashing device to control Piccolo's mind, forcing him to fight against Goku. This creates a difficult situation where Goku must defend himself against his ally without causing serious harm.

Wheelo demonstrates control technology early by keeping his own brain alive in the lab.