Jib Janeen (Paul F. Tompkins) is a Jupiter Spy who was sent to Mars to spy on Sparks Nevada and other important Mars denizens in order to learn their secrets. Like all Jupitarians, he can take the physical form of anyone he chooses.
Jib was sent to Mars by Queen Quaflix to perpetuate the birthright of Firmso.
History
In Something Wicked This Way Is, Janeen impersonates Sparks Nevada, attempting to learn the secrets of Mars and everyone's passwords. He nearly is able to incite a riot on Mars by turning Croach the Tracker, Felton, The Barkeep and The Widow Johnson against each other, but his final fear-mongering speech had the opposite effect, and instead, inspired everyone to work together.
In The Thing From This Same Planet!, Janeen impersonates Croach. While Doctor Muller attempts to use DNA tests to try to figure out who the Jupiter Spy is, and warns them all against the Infectoid Geigameiter, Janeen continues to attempt to discern secrets and passwords. He is witness to The Red Plains Rider announcing her pregnancy.
In Father Reaches of Space, Janeen impersonates Cactoid Jim, and proposes to the Red Plains Rider, who rejects the proposal and declares the baby to be Sparks Nevada's. Jib also knocked out Cactoid Jim before this episode, and tied him up and put him in a cave, later freezing him in carbon and selling Jim to some aliens who were mad at him.
In Into Darkness, Janeen has been impersonating former USSA X.O. Antoinette Fontaine after killing her husband and freezing her in carbon as well. He convinced Captain Manlius of the USSA starcraft he was aboard to go to Mars as "she" was sure the Jupiter Spy was there. Once Jib beamed down to the planet while The Red Plains Rider was in labor, he announced Red's baby was hers, and she was just the incubator. He left the planet in his spaceship with his baby.
In Natal Attraction, Jib had been impersonating The Widow Johnson while spending time with Felton. Once Felton and Croach both go into labor, he announces both babies are his, and explains that Jupiterians impregnante others by kissing. Jib says he impregnated Croach while pretending to be Sparks, and attempted to impregnante Sparks as well later (probably while pretending to be Croach) but Sparks was not able to bet impregnated. When Doctor Muller enters, being chased by an Infectoid Geigermiter, Jib uses everyone's weapons to fashion a transport device that only sends himself and the two Jupitarian babies back to Jupiter.