Wendy Taylor was the young daughter of a family of mutants which included her father, mother, and brother Billy. The children got into an argument about whether or not "monsters" employed by the government kidnap people, only for those very monsters to arrive in the form of the Weapon X Program, represented by Kane, Sauron, and Wildchild. Mr. Taylor attempted to buy enough time for his family to escape from them, but Mrs. Taylor and her children found their exit blocked by Marrow, Washout, and Sabretooth. Though they attempted to use their powers on the attackers, they were put to sleep by Mesmero.
The Taylors were taken to Neverland, the mutant concentration camp, where Billy befriended Maggott, another inmate. The Taylors were branded with green 'M's on their hands, denoting powers useful to the Program. Those branded with red 'M's, like Maggott, were immediately put to death upon arrival, with Maggott giving one of the slugs that were his digestive system to Wendy beforehand. When Mrs. Taylor became too weak to move from the experiments the Program performed on her, she arranged for a passage out of Neverland for her children, by way of Project scientist Dr. Windsor.
Unfortunately, it was all for nothing, as Dr. Windsor was actually Mr. Sinister, who continued experimenting on the children. Sinister injected Wendy with a chemical the prompted a secondary mutation of spikes growing from her body, and though it appeared this killed her along 182 others subjects (including her brother), she in fact survived.
Her and her brother's final fates in Sinister's hands were unrevealed.
Powers and Abilities
Gaseous Form: Wendy appeared to possess the ability to dissolve into a gaseous state. Her eyes glowed yellow when she used her powers.
After being experimented on by Mr. Sinister, Wendy developed a new mutation of red spikes covering her body. It is unknown what, if any, function these had.