Meglos

The last surviving Zalfa-Thuran, a cactus-like species that could transfer its genetic structure and mind into any other creature, or create a duplicate o someone. Seeking the power of the Dodecahedron that powered the planet Tigella, Meglos hired the Gaztak mercenaries to bring an Earthling to Zalfa-Thura, so as to gain mobility. He later adapted a copy of the Doctor's body and return to Zalfa-Thura, using vast screens erected there to give himself power. The Doctor however, realigned the screen; Meglos was exterminated along with his underground laboratory when the Dodecahedron's power was directed towards him.

Meglos was only in Meglos.