J-5

5 was an alien waif with pointed ears encountered by the Robinsons shortly before they left a planet. He could create illusions that seemed real and carried a sometimes invisible creature called a Zaybo around with him. He could pilot the Jupiter 2 by just seeing where the controls were, and could sense which control panels had short circuits and which did not. He left his home planet when he was very young to colonize the same planet the Robinsons eventually reached. The Robinsons took J-5 with them when they left the planet, and at the end of "The Haunted Lighthouse" he remained with Colonel Fogey on the Space Lightship F-12.