|Voiced by||Alan Oppenheimer|
Before Nexor and his traveling companions Zorgon and a third, Unidentified Alien arrived, their Alien Spaceship encountered Prime Evil, who managed to take control of the space vehicle and marooned Nexor and his friends on a dangerous, uninhabited Asteroid.
Just before their supplies and oxygen ran out, the three aliens were found by the Ghostbusters and Futura, who had borrowed the spaceship from Prime Evil's ghosts. Nexor was the last to be rescued, after using his last strength to crawl valiantly towards his Spaceship while in danger of being hit by falling asteroids.
Alghough Zorgon had grown weary of meeting any more Earthlings and refused to set foot on Earth or help the Ghostbusters in defeating Prime Evil, Nexor managed to convince Zorgon that there was still good in mankind and to lend the Ghostbusters a hand.
After defeating Prime Evil, Zorgon and the other two aliens finally met the President of the World Federation in greeting. Before the Ghostbusters left to return to their own time, all three of the aliens autographed Tracy the Gorilla's Baseball Bat, which the Ghostbusters proudly mounted on a wall at Ghost Command.
Nexor first appeared in the episode That's No Alien.