In 2001, 20th Century Fox sued Marvel Entertainment, stating "Mutant X" violated Fox's film rights for X-Men (2000). As a result, several changes to the premise of the series were made to distance it from the movie and its comic-book source material. Originally, the "mutant" characters were to have worn black costumes and used codenames (just as in X-Men), and Adam was to have been a wealthy mutant with the surname of Xero (similar to Professor Xavier). The show's logo was also changed from its initial design, which featured the "X" behind the word "Mutant," which resembled the logo used in trailers and TV ads for X-Men (2000) ("X" behind "Men").
Even though the series had high ratings and had been renewed for a fourth season, it was abruptly canceled in 2004 due to the dismantling of one of the production companies.
There are four mutant classifications: Feral, Elemental, Molecular, and Psionic. Feral mutants had their DNA spliced with an animal whereas Elementals can channel environmental and/or elemental energy through their bodies. Molecular mutants have abilities which defy physical science such as invisibility, propulsion, chromatic (color), intangibility (move through solids), and so forth. Finally, Psionics possess heightened mental abilities. Common psionic types include: Illusionist, Telepathic, Precog, Telempathic, and Telekinetic.
The code names for the characters of the show before they were dropped because of legal action were "Fuse" for the electricity throwing Brennan, "Rapport" for the empath Emma, "Shadowfox" for the animal-like Shalimar and "Synergy" for the density changing Jesse.
Mutant X was the name of a version of the X-Men on a parallel world in the HAVOK miniseries; it was also the name of an unknown mutant character.