From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Doctor Lychee (ドクター ライチー, Dokutā Raichii) is a Tsufruian scientist.
Doctor Lychee's Japanese name is a pun on the word Reishi, or Lychee in English.
In his prime, Lychee was the greatest scientist of his race. Eventually, the Saiyans not only massacred the entire Tsufruian race, but also stole their technology and conquered the planet. They later renamed it Planet Vegeta in honor of their king. Lychee made a desperate attempt to escape with his most esteemed invention, Hatchiyack, but was killed before his spaceship prepared for liftoff. The spaceship did launch and eventually landed on Planet Dark, a world at the end of the universe. Hatchihyack continued to incubate until it conceived the Ghost Warriors, among them a renewed Lychee whose only wish was to eradicate the last remaining Saiyans.
The scientist later released Destron Gas on Planet Earth, which disturbed the Z Warriors' concentration in using ki attacks. They defeated the minions who guarded the Destron Gas generators, but Ghost Warriors of past villains appeared and attacked them. This was all part of Lychee's plan to lure Son Goku, Son Gohan, Future Trunks Brief, and Vegeta (the last remaining Saiyans) to Planet Dark. Once there, they fought against Lychee, whose only attack was a barrier. Once the barrier was shattered, Vegeta blasted Lychee with the Final Flash. After Lychee rematerialized and tried to form a shield once again, Vegeta brutally executed him, shattering the barrier along with him. When a small fragment of Lychee fell to the ground and screamed with all of his hatred of the Saiyans, Vegeta crushed what remained of him under his foot.
Lychee appeared in Dragon Ball Z Gaiden: Saiya-jin Zetsumetsu Keikaku and the remake, Dragon Ball: Plan to Eradicate the Super Saiyans.
Doctor Lychee appeared in Dragon Ball Heroes.