Origin

The Wild Sentinel was apart of a secret US government operation into developing and creating new versions of Sentinels in the event of a all-out war between mutants and humans. This project was seemingly abandoned when Bolivar Trask alongside the primary Master Mold were destroyed, leaving them abandoned for decades within their programed "test field" deep within Ecuadorian rainforests wherein they cannibalised scrap metal and any source of technology possible to duplicate and create more Sentinels. Cassandra Nova manipulated Donald Trask III into giving her full access to the site, killing him after fully copying his DNA structure over a period of ten hours.

Nova then removed the test field restriction, allowing the Wild Sentinel to grow monstrously huge by integrating immense amounts of technology adapting into a supersonic jet plane. Having smashed into Genosha, it quickly was able to annihilate a vast majority of the population there but then deactivated after Cassandra Nova was captured: having no one left, Trask or otherwise to provide it orders. The inert carcass nevertheless stood within the ruins of the once-mutant capital of the world as a memorial to those who were ruthlessly killed that day. When Genosha was fully abandoned the second Wild Sentinel fell into the ocean and was left buried there.

Creation

The Wild Sentinel was created by Grant Morrison and Frank Quitely, first appearing in New X-Men #114.

Return

Danger, a rogue software based around the protocols and knowledge built from the physical Danger Room as apart of its revenge on its creator went to Genosha and managed to reactivate the Wild Sentinel. Noticeably it also barred it accessing the original directives provided by it by Cassandra Nova, instead attempting to use it as a weapon to destroy the X-Men in the ruins of Genosha alongside Xavier. Though almost victorious, a intervention by Kitty Pryde prodding it to investigate those directives caused the Wild Sentinel to become remarkably regretful; having developed to the point of having a conscience, it was incapable of processing such significant loss of life and swiftly retreated to "spend some time alone" dealing with its newfound sentience having seemingly left Earth in the process.

Destruction

The Wild Sentinel made a final appearance attempting to divert the Breakworld Bullet from destroying the Earth by ramming itself right into it before it could reach the planet. This, sadly, was not successful, and the damage sustained from such a feat was seemingly far too much for it to rebuild itself back together.