Supergirl acknowledged its big recasting of the famous Superman villain Mister Mxyzptlk in the Arrowverse show’s milestone 100th episode. The Melissa Benoist-led drama became the Arrowverse’s third show to hit 100 episodes, following in the footsteps of Arrow and The Flash. For Kara Zor-El’s celebratory event, it focused heavily on the complicated status of her relationship with Lena Luthor (Katie McGrath). Before making his debut, it had been revealed that Thomas Lennon was joining Supergirl as Mister Mxyzptlk.
While Mister Mxyzptlk previously appeared in Supergirl season 2, the role was initially played by Peter Gadiot for a 2-episode arc. Gadiot’s take on the character didn’t return after that as it would take almost 3 seasons before Supergirl decided to use him again. The news arrived in the midst of Crisis on Infinite Earths taking place, with the 5-part crossover shaking up the status quo for all the shows, including Supergirl. This wasn’t the first time that a major part of the series was recast, as Kara’s mother Alura had two actresses playing her, starting with Laura Benanti who was then followed by Smallville’s Erica Durance.
Given the nature of Alura’s role in the show’s continuity, there was never any room to make any remarks on her suddenly looking different than before. However, with the character of Mxyzptlk being a fifth-dimensional imp with major powers, Supergirl ended up embracing the big change. After showing up at her doorstep unannounced, Kara and Alex (Chyler Leigh) had no idea who this man was. Lennon’s incarnation of the DC foe is at first not believed by the sisters that he is the bugging imp from years ago. Through a snap of his fingers, Mxyzptlk pulls up the footage from Gadiot’s episode where he tried to get Kara to marry him. When asked why he looks like this, Mxyzptlk begrudgingly explains that he only did it to impress the last daughter of Krypton.
Due to the fact that Kara defeated him the last time they saw each other, it’s preventing him from using his powers except to help those who he had wronged previously, including Kara. That’s what sets up his role in “It’s a Super Life” by trying to help Kara fix her relationship with Lena through the magic of time-travel. This is, however, not the only time where Supergirl broke the fourth wall with Mxyzptlk's recasting. Later on in the 100th episode, in one of the alternative timelines, Kara brings Mister Mxyzptlk with her when she finds the rest of her Super-Friends. When asked by Martian Manhunter (David Harewood) who he is, after the reformed villain introduces himself, Mon-El (Chris Wood) brings up what the imp tried to do the last time they met.
While it seems like Lennon’s Mister Mxyzptlk will be on Supergirl for the long-run, it’s neat that this was a recasting that even the show could acknowledge. In most cases with other shows, it’s trickier to make any remarks on a character’s recasting depending on the genre and tone of said character. But with Supergirl being a superhero drama that is using one of the more comic book-y characters from DC, it paved the way for an organic commentary by other characters about Mxyzptlk’s new look. According to the original casting report, Lennon will recur this season which could mean that there is potentially more to come from Mxyzptlk in the rest of Supergirl season 5.