The Jupitarians are the native denizens of Jupiter. Many choose to become spies. They spread destruction in the cultures they infiltrate with the weapons of thoughts, attitudes and prejudices, then with bombs and explode-y things.
- Jupitarians are ruled by Queen Cloffix, who sent Jib Janeen to Mars to order to perpetuate the birthright of Frmxo.
- They have many torture implements.
- They also have "many" gods.
- "Jupe" is a slur on their species.
- "Jupiter-rig" is a slang term among Jupitarians for making makeshift repairs or temporary convinces with only the materials on hand, but they don't really like it when you say it like that.
- Jupitarians celebrate Christmas. One tradition is to invite the first person who they impregnated on each planet to their Christmas parties. 
- Most people on Jupiter are spies.
- The Jupitarian flag is red and white striped. 
- Jupiterians have three hearts, the most of any species. (Note: Mutants are born with "any number of hearts" so there may be some mutants that actually have more hearts than Jupitarians)
- Their true forms are very purple.
- Jupiterians' unique biology allows them to take the physical form of anyone they choose, down to their DNA. The Jupiterian both looks and sounds exactly like their subject, and can even fool Martian senses.
- Stripes are the most difficult pattern for a Jupiterian to shapeshift into, with red and white stripes being the most difficult color and pattern.
- They have at least two endocrine systems.
- Their hands are webby.
The host acts as incubator for the child, which releases a toxin to make the host care for it.
The child's DNA, when tested, appears to show the mingled DNA of the host and the person whose form the Jupitarian parent had taken when they had impregnated the host, but is, in actuality, solely the DNA of the Jupitarian parent.
They nourish their children with a saline solution created with their secondary endocrine system.
- T-Minus (TAH #58)
- Mercy Killing (TAH #86)
- Wanted Men (TAH #127)
- Carbonite-mare (TAH #148)
- La Venganza de Los Bandititos (TAH #157)
See Jib Janeen's appearances.