Men in Black 3 (2012)

In 2012, an alien criminal named Boris the Animal, the last Boglodite, escapes from a maximum-security prison on the Moon to take revenge on Agent K, who shot off his left arm and captured him in 1969. He confronts K and his partner Agent J, and tells him he is “already dead”. Back at MiB Headquarters, J discovers K was responsible not only for capturing Boris, but for deploying the “ArcNet”, a shield that prevented the Boglodites from conquering Earth, leading to their extinction.

Boris travels back in time to July 16, 1969, to kill the young Agent K, altering history. With only J’s memory somehow unaffected, no one else at the Agency understands his inquiries and knowledge regarding K until Agent O, the new Chief of MIB following Zed’s death, eventually pieces together J’s erratic actions as signs that there has been a fracture in the space-time continuum. With K gone, the ArcNet was never deployed, and present-day Earth is defenseless from a Boglodite invasion. Knowing from the Agency’s records Boris will commit a murder at Coney Island on July 15, 1969, J time travels to said date to kill Young Boris. However, he is arrested by young K, who takes him to MiB Headquarters and prepares to neuralyze him, but decides at the last minute to investigate his claims that he traveled from the future to stop Boris. K and J follow clues, leading them to a bowling alley, and then The Factory, where undercover MiB agent Andy Warhol directs them to Griffin, the last Archanan.