Ultron

Ultron was an artificial intelligence peacekeeping program created by the minds of Hank Pym, along with some aid from Tony Stark and eventually Bruce Banner. with the intent of protecting Earth from all new domestic and extraterrestrial threats. Possessing multiple host bodies under his control as well as a variant of Stark's own personality, Ultron soon deemed humanity itself as the greatest threat to peace on Earth and attempted to create a technological singularity by committing genocide against them and restarting the entire world in his image.

With initial aid from enhanced twins Pietro and Wanda Maximoff and a mind controlled Moon Knight, Ultron fragmented the Avengers briefly, but was abandoned by his allies when they discovered the truth of his genocidal intentions. Alone, he tried to use a device composed of both vibranium and Chitauri technology to recreate the mass extinction event that eradicated the dinosaurs. He nearly would have succeeded, but both he and his plans were destroyed by the Avengers. Even after his defeat and destruction, the effects of Ultron's actions led to the creation of the Sokovia Accords and the igniting of the Civil War, orchestrated by Helmut Zemo.