The Mutants (also commonly referred to as Mutant Beasts) are a powerful group of beast warriors who've lost their robot modes, but are able to transform between two beast modes. Led by Icebird, the Mutants seek to create a purely organic existence. The Mutants don't belong to either faction, and will attack Predacons on sight, but they largely tolerate the Maximals as a necessary component of their goals.
Megatron developed an anti-conversion virus, intended to prevent the infected host converting into robot mode, resulting in eventual shutdown. The Mutants were previously Fuzors, and the virus reacted in an unanticipated way with their physiognomy; it caused their conversion abilities to change, trapping their robot modes between two different beast modes. The virus also bestowed 'potent extrasensory powers' upon the former Fuzors, with each member having several unique abilities, such as invisibility, teleportation, or technokinesis. Unsurprisingly, the foursome managed to escape Megatron's clutches and then went renegade, calling themselves the Mutants.
Universe: The Wreckers comics
The Mutants, on Megatron-dominated Cybertron, reported along with the Dinobots and the Wreckers to the Oracle and were given a mission to fullfill: to save the planet's future. It was all a set-up, however, by Cryotek and the Quintessons. The Mutants' instructions led instead to their apparent deaths by Sharkticons, although Poison Bite was later seen concealed in Cryotek's headquarters - evidence that the reports of their deaths may have been greatly exaggerated.
The remaining stasis pods from the Axalon were activated by Razorbeast. The majority of the newly-born Transformers were either Maximal or Predacon. But a few were born Mutants. They fiercely defend their swamp against intruding Predacons, making it clear that no Transformer is welcome in their peaceful home.
The four toys in this sub-group were originally designed for the ill-fated Animorphs toyline, and upon its failure were slightly retooled and brought over to the mainline Transformers continuity family. They have a couple of common features. Each toy had a robot head hidden somewhere within its body, to indicate that their personas were still essentially sentient rather than bestial. Also, three of the four toys had flip-up panels underneath their Mutant insignia, which were lifted to reveal robotic components (to convey they were still essentially robots, although they lacked a 'robot' mode); for some reason Razor Claw lacked this feature.
- The exact placement of these characters within the fiction can be argued. Though their packages labeled them "Beast Wars" they came out at a point when the Beast Wars toyline and cartoon were well ended and Beast Machines was well underway. Further, their backstory and techspecs make reference to Megatron's mode-lock viruses, conflict between organic and mechanical Transformer life, and most tellingly the Oracle, all of which were specifically central points of the Beast Machines era storyline. Hence, the 3H Botcon materials placed them on Beast Machines era Cybertron as part of that conflict, while the IDW comics defaulted to their packaging label, ignored any conflicting backstory, and made them a part of the Beast Wars on Earth instead.
- Whether by design or coincidence, the beast-to-beast Beast Changer toy was released in the main Beast Machines toyline at nearly the same time as the Mutants.