Origin

As part of the Secret Invasion, numerous Skrulls were ritualistically altered in order to evade detection while on Earth. The Skrull impersonating Ms. Marvel was sent to sow discord among the real heroine's Lightning Storm squad.

Creation

The Skrull Ms. Marvel was created by Brian Reed and Adriana Melo. Her first appearance was in Ms. Marvel #25 - The Secret Invasion!: Part 1 (May 2008).

Ms. Marvel: The Secret Invasion

As one of the Skrull infiltration agents, the alien impersonating Ms. Marvel used her shape-shifting powers to get close to William Wagner - a disguised Kree agent and the current boyfriend of Carol Danvers. Killing Wagner, the Skrull left before the real Carol arrived and allowed Danvers to take the blame for Wagner's murder. As Ms. Marvel battled her various Lightning Storm teammates - Agent Sum, Machine Man, and Sleepwalker - the Skrull returned. After trading blows, both women were taken into custody in the hopes of determining the identity of the Skrull subversive.

Unable to separate the Skrull from the real deal, the situation became more complicated with the revelation that the Warskrull Rl'nnd had infiltrated the SHIELD ranks. As the Skrull Ms. Marvel watched from captivity, Carol Danvers succeeded in killing Rl'nnd, causing her doppelganger to revert to her true alien form.

Using her knowledge of Wagner, the Skrull sent Ms. Marvel on a wild goose chase in search of the Kree agent's body. Realizing that she had been played, Danvers sped back to her team's location. However, she was too late to prevent the Skrull infiltrator from acting as a suicide bomber, destroying the Lightning Storm minicarrier, killing and wounding numerous agents, and striking a blow for the Secret Invasion.

Second Version

A second Ms. Marvel Skrull was found in the Savage Land, wearing the classic red costume of Carol Danvers. This one, like her many brainwashed compatriots, was revealed to be a sleeper agent and killed battling the Avengers.