: Barry Allen and Bruce Wayne team up to investigate a blood-stained smiley face button found in the Batcave.
One of the most famous versions of The Flash #21 was published in 2017 as the second part of " The Button ". This storyline directly connected the world of the Flash to the mysterious Watchmen universe. Flash 21
In more recent stories (2025), The Flash #21 has explored even weirder cosmic horror. : Barry Allen and Bruce Wayne team up
: The issue features a shocking confrontation with Eobard Thawne, the Reverse-Flash, whose mysterious death sets the stakes for a reality-shattering adventure. In more recent stories (2025), The Flash #21
: The story offers tantalizing glimpses into Bart's origin in the 31st century.
: It highlights the unique bond between Batman and Flash, grounded in their shared love for forensic science. When Barry Met Bart: The New 52
In the world of DC Comics, "The Flash #21" has been the title of several major turning points across different eras. Whether you’re looking at the iconic "The Button" crossover or the first meeting between two generations of speedsters, these issues are legendary for redefining what it means to be the Fastest Man Alive. The Button: A Collision of Worlds