Lord Slug

Lord Slug arrives on Earth as an elderly Namekian aboard a planet-sized cruiser, seeking the Dragon Balls to restore his youth. After successfully wishing himself young again, he reveals his plan to terraform Earth by blanketing the planet in an artificial atmosphere that blocks sunlight, creating an environment more suitable for his species. His army begins enslaving the human population while Slug prepares to use the frozen Earth as a mobile base for further conquests.

Goku confronts Slug and initially struggles against his rejuvenated power. The villain transforms into a Great Namekian, a massive giant form that amplifies his already considerable strength. Slug believes this form makes him invincible, but Goku receives an energy transfer from Piccolo and uses Kaio-ken multiplied to extreme levels to penetrate Slug's defenses. The battle concludes when Gohan and Krillin expose Slug to high-pitched whistling, exploiting the Namekian weakness to certain sound frequencies, giving Goku the opening he needs to destroy the tyrant.

Lord Slug represents a "what if" scenario for the Namekian race: a warrior who embraced his darker nature rather than the guardianship and wisdom that Piccolo eventually chose. His existence as a Super Namekian born from evil mirrors King Piccolo, suggesting that the potential for both great good and great evil exists within the Namekian species. Though he appears primarily in a standalone film, his concept enriches the broader lore of the Namekian people.