Secondary mutation

In the Marvel Universe, Secondary Mutation was a fictional worldwide phenomenon among mutants that seemed inexplicable, with many previously established mutant characters suddenly developing new or vastly expanded powers. Henry McCoy hypothesized that since the mutant population was entering the millions at that time, that mutant physiology was responding to the need for survival. Thus in rare occasions a mutant's powers change or become even greater, and in rare cases they can develop a new, often unrelated ability. However, the criteria for secondary mutation is ill-defined at best, leaving many fans confused as to their favourite character's status on the evolutionary chain. This use of secondary mutations can sometimes be misused as a Deus ex machina; if the writer can't think of a way for a character to get out of a situation, they can simply develop a spontaneous new power to handle the problem.

Known mutants with secondary mutations

• Polaris (Lorna Dane): after having her mutant powers leeched by her supposed-sister, Zaladane, Lorna developed the first known case of secondary mutation. Her body mass had increased, along with her strength. When her secondary powers were used, it developed negative emotions in anyone around her.

• Beast (Hank McCoy): after being seriously injured by the villain Vargas, Sage attempted to use her ability to "jump start" mutation to save his life. This resulted in Beast de-evolving from his simian form into a giant feline form.

• Emma Frost: Emma's secondary mutation activated in the midst of the bombing of Genosha by Cassandra Nova's wild Mega-Sentinels. She transformed into an indestructible organic diamond form that saved her life, but negates her telepathy so she cannot use both powers at once. Recent revelations suggested that it may have been Nova who helped produce the secondary mutation. It was later explained that Cassandra Nova implanted a suggestion in Emma's mind in an attempt to eventually make an escape from the Shi'ar alien protoplasmic Stuff. The X-Men believed themselves to be fighting various members of the Hellfire Club, only to learn that they were illusions created by Emma's subconscious mind.

• Angel (Warren Worthington III): discovered his new power while being wounded in a battle with a group of werewolf-like mutants called the Dominant Species. Both he and his teammate Husk were severely wounded. Husk actually died, but was brought back through contact with Warren's blood seeping in through wounds on her own body. His blood gained a healing property that can be used to mend and regenerate others. However, this ability first manifested in a battle against Black Tom Cassidy, when his skin turned from blue to normal (as a result of his healing factor activating). Angel had previously been modified by Apocalypse; whether this included genetic alterations has never been clarified.

• Iceman (Bobby Drake): his secondary mutation was not as beneficial as some of the others, greatly increasing his ice manipulation abilities, but leaving him trapped in his organic ice form and unable to transform back to flesh and blood. However, after the events of M-Day, where over 99% of the world's mutant population became depowered, Bobby is once more able to revert back and forth. This leaves the question of whether his second mutation was a transformation into ice or just an increase in his power he had to overcome.

• Elixir (Josh Foley): used his biokinetic powers to return to Rahne Sinclair's ability to shapeshift into a wolf. At first, she was unable to control it, severely wounding Josh, only to be scared away through the pheromone powers of Laurie Collins, a fellow student that had a crush on Josh. Josh lay dying in the infirmary, kept comfortable with drugs fed through an IV. Another student, David Alleyn suggests that they wake Josh, as he could heal himself. Using Noriko Ashida's electrokinetic power to shock Josh awake, then Laurie's pheromone powers to calm him, Josh was able to heal himself. As a result, his hair and skin were turned to a reflective gold shade that Dr. Hank McCoy theorized was some type of secondary mutation, unlocked by the trauma and the healing.

• Husk (comics) (Paige Guthrie): After shedding her skin revealing rubber, she experienced super speed. Her speed allows her to out-run bullets.