Abel Crumpton

 appeared to be a human from Earth but was actually a Garvak.

Crumpton obliterated the planet Zantor and stole the Egg of Abundance that contained the genetic imprint of Zantoran life. The last two Zantorans, Lettice Butts and Radcliff, were assigned to retrieve the Egg.

Crumpton was having Lettice followed and, when she recruited Harry Sullivan to help her, captured and tortured Harry for information. He also captured Lettice, intending to use her to unlock the Egg and rewrite it, using it to create a Garvak empire on Earth.

Crumpton was defeated when Harry switched the Egg with an egg, and, when the egg was in Crumpton's machine, it focused the egg's power and turned all the assembled Gavraks into chickens. The machine then burst into flames, killing all the chickens. (PROSE: The Man from DOCTO(R))