The Flash: 10 Best Characters Who Only Appeared In One Episode

These characters' speedy appearances definitely stood out over the years.

The Flash Solovar
The CW

Ever since Arrow bowed out in 2020, The Flash has become the Arrowverse's longest-running show, boasting a massive eight-season count. Although the series' best days appear to be behind it, the adventures of Barry Allen and Team Flash show no signs of slowing down.

Naturally, due to the show's longevity, a myriad of characters have come and gone over the years. The series saw the first live-action appearances of beloved rogues such as Reverse-Flash, supporting characters such as Wally West, and even gave the Speed Force itself an avatar of sorts. These characters impact on the show cannot be understated, and they've helped flesh out the greater Arrowverse.

While these figures are beloved DC mainstays, some characters have not had the opportunity to be part of season-long arcs or make recurring appearances. That said, their one-off appearances left an impression on fans due to their faithfulness to the source material, solid performances and their position in the show's overarching narrative.

From underrepresented DC heroes and villains, to unexpected but amusing cameos from beloved film characters, these names have had all had extremely memorable one-off appearances in The Flash.

10. Atom Smasher

The Flash Solovar
The CW

The Flash's second season saw the introduction of the Multiverse as a concept, and this forever changed the landscape of the Arrowverse into the sprawling franchise we know it to be today.

Albert Rothstein/Atom Smasher of Earth-2 holds the distinction of being the first multiversal character introduced in the show, and while his appearance was merely the first in a long line of visitors from parallel worlds, it signaled a massive shift in the show's narrative direction and ambitions.

WWE superstar Adam "Edge" Copeland gave the role an intimidating physical presence (in addition to the CG enhancements) and sold the character's fear of Zoom fairly well.

The size-changing metahuman was forcibly recruited by the murderous Hunter Zolomon/Zoom to kill the Flash of Earth-1 in exchange for his safe return to his home dimension. Rothstein instead chose to hide on Earth-1 and murder his doppelganger so as to trick Zoom into thinking that he was dead.

Unfortunately, this did not work out as planned and Rothstein was forced to go on a rampage throughout Central City, which culminated in his death at the (indirect) hands of Barry and his team.

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