Professor Richard Impossible (voiced by Peter McCulloch in “The Terrible Secret of Turtle Bay”, Stephen Colbert in seasons 1 and 2, Christopher McCulloch in season 3, Bill Hader in season 4), also nicknamed Dicky. Founder of Impossible Industries, a major government contractor, and former professor to Dr. Venture, Mr. White, and Billy Quizboy. He holds science and the pursuit of knowledge in a much higher regard than he does his wife or other people; at times this has made itself manifest as homicidal ruthlessness, though most of the time he’s simply out of touch. Impossible and his cohorts are a parody of the Fantastic Four: an experiment with cosmic radiation gave them each strange abilities (this parody is referenced explicitly in the episode “Love Bheits” when it is mentioned that the Impossibles beat the Ventures in a costume contest by dressing as the Fantastic Four). Richard can stretch his body like rubber, similar to Mister Fantastic, and seems to use this power to make himself appear taller. The other members of his family have useless parodies of the other members’ powers. Jackson Publick’s blog states that Colbert’s representatives have said he has neither “the time nor the interest” to further voice Professor Impossible. According to Publick’s most recent update, Bill Hader will provide Impossible’s voice in Season 4.
Sally Impossible (voiced by Mia Barron): Richard’s estranged wife. She has invisible skin which leaves her muscle tissue visible (which is significantly less useful than the abilities of the Invisible Woman) and she requires all her concentration to keep her skin visible. This power is occasionally referred to as her becoming “visible” (making her “the visible woman”). She does not show any ability to create forcefields like her Marvel counterpart. Sally developed, and still maintains, a crush on Dr. Venture, who was repelled when he discovered her condition. Richard has implied that she has been repeatedly unfaithful and that her newborn son might be fathered by someone else, although this may have been Richard being very callous, and not a grounded accusation. This is a reference to the Invisible Woman’s relationship with the Sub-Mariner, who has pursued her romantically from their first encounter. Eventually, it came to the point where Richard was keeping Sally practically as a prisoner in their home and keeping her under constant guard, accurately suspecting that she wanted to run away from him. Sally has been dating Jonas Venture Jr. and resides on Spider Skull Island with the rest of the Impossibles, sans Richard.
Rocket Impossible: Sally and Richard’s newborn son. Thus far, he has not displayed any sort of super powers or genetic mutations. He is a parody of Franklin Richards, son of Mr. Fantastic and the Invisible Woman. Richard has previously voiced concerns that he may not be the father.
Ned (voiced by Christopher McCulloch): Sally and Cody’s mentally-handicapped cousin, who has been transformed into a “giant callus” with three-inch thick skin. He has a pale orange, lumpy appearance. He is stronger than ordinary people, but not nearly as strong or impervious to harm as the Thing.
Cody (voiced by Christopher McCulloch): Sally’s brother. Bursts into flames when exposed to oxygen. Unlike the Human Torch, he cannot control this very painful reaction, so he is kept in an air-tight container. As a result, he is usually in a state of unconsciousness. It is unknown whether he was brought to Spider Skull Island by Jonas Jr. with the rest of his family or if he’s still under the control of Professor Impossible.