The USS Corregidor (NCC-41606) was a modified Galaxy-class (variant design) Federation starship from an alternate timeline. During the latter decades of the 24th century in this timeline, the Federation had fallen to invasion by a race known as the Usurpers. Corregidor, one of a handful of Starfleet vessels which withstood the assault, traveled through time in a failed attempt to prevent the invasion, emerging in early 2387 in the UFS Arcadia's temporal reality.
Due to the intricacies of temporal causality, the ship's commanding officer, Feynman, accidentally erased the Corregidor from existence, becoming the only surviving crewmember. Feynman suffered a traumatic mental breakdown and committed suicide as a result. (Star Trek: Arcadia)