DC Comics' Flashpoint by Geoff Johns and Andy Kubert featured Barry Allen going back in time to prevent the death of his mom, Nora, at the hands of the Reverse-Flash. While the Flash was successful at saving his mom, the decision to travel back in time severely messed with the DC timeline. The Justice League never formed, Superman isn't around, the Ezra Miller and Michael Keaton starring Flash film in the DCU.
When Barry tries to navigate through the alternate universe he created, he ends up in Batman's Batcave. While Batman does exist in Flashpoint, it turns out that Thomas Wayne is now the Caped Crusader. Reversing Bruce Wayne's origin, Thomas and Martha survived Joe Chill's robbery in the Gotham alleyways, and their son was killed instead. While Martha became the Joker in Flashpoint, Thomas would become the Dark Knight - however, with a different set of morals. While Bruce's Batman has a no-kill rule, Thomas' Batman isn't bound by such rules. In his first encounter with Barry, Batman pummels him before the speedless Flash can tell him the truth. It's also Thomas who kills Eobard Thawne, as the villain reveals it was Barry's fault the timeline was so messed up.
Flashpoint Batman is a killer who isn't afraid to get his hands bloodied in order to get the job done. Sadly, he's mortally wounded by the Enchantress as the universe begins to fall apart. But, he gets a happy ending of sorts realizing that he helped restore the timeline and got to give his lost son a touching letter. But, wait... that was not the last Flashpoint Batman story.
Flashpoint wouldn't spell the end of Thomas' arc, as it's revealed in 'The Button" storyline that he's still alive. However, he's seemingly erased from existence after meeting his adult son. He was again brought back in Tom King's Batman run, as he tries to convince his son to stop being the Dark Knight. In that arc, he shoots Bruce and nearly kills Bane. While his intentions aways seemed to be in the right place, Thomas Wayne's killer version of Batman crossed lines his son never would. In doing so, he ultimately met his end... until DC decides to bring him back again - or Barry messes the timeline up even further and creates an even worse Batman.
