Travella the shapeshifter

Travella was an Orion who was also a shape-shifter. He could transform into an Andorian, which came in handy because Travella was serving a life sentence on the Klingon penal colony of Rura Penthe. Travella met Captain Kirk and Dr. McCoy, who were also on Rura Penthe. Kirk and McCoy were convicted of a crime that they didn't commit: assassinating Chancellor Gorkon. Travella helped Kirk and McCoy get out of the beaming shield so that the USS Enterprise-A, commanded by Captain Spock, could rescue them. The Enterprise-A beamed Kirk, McCoy, and Travella aboard.