Bolog

Bolog was an alien who once concealed the whole Reptilios Invasion Fleet on the dark side of the Moon in their effort to conquer the Earth. However, the Fourth Doctor sent the Fleet into orbit with a banana.

Some time later, Bolog joined forces with other aliens that had been defeated by the Doctor to try to kill him. He shot Questor in the face, believing him to be the Doctor in disguise.

Later, caught in a three-way shoot-out, he was shot by Plink and simultaneously killed the Mentor. (COMIC: Death to the Doctor!)