Warning: Contains SPOILERS for Superman & Lois
The villain plot of Ally Allston on Superman & Lois is the inverse of a Lex Luthor story on Smallville, with both still achieving the same thing with their characters. With Superman & Lois on break until May 31, viewers are awaiting the Man of Steel's final battle with cult leader Ally Allston (Rya Kihlstedt). In her last appearance in the episode "Bizarros in a A Bizarro World", the main Ally viewers have seen merged with her Bizarro self, setting her up as a vastly powerful villainess for the final stretch of Superman & Lois season 2. This is an approach previously seen in an earlier Lex Luthor Smallville story.
Smallville went the opposite direction from Superman & Lois' story of merging entities with its season 4 episode "Onyx", in which Lex Luthor (Michael Rosenbaum) is split into two people by black kryptonite. The new Lex is a truly evil counterpart to the original Lex and to the friend of Tom Welling's young Clark Kent, chaining the first Lex in his basement and attempting to coerce Clark into joining forces with him. While "Onyx" did the flipside of "Bizarros in a Bizarro World" in separating Lex, both Smallville and Superman & Lois were and are doing the same thing in revealing a villain for their true self.
Ally's endgame is to merge her cult of followers with their Bizarro selves, unlocking the full power they possess when merged together. With the two Ally's joined as one, what she'll unleash for Superman & Lois' season 2 finale will show her at her villainous peak. Meanwhile, by splitting Lex into two people in "Onyx", Smallville gave viewers a look at Michael Rosenbaum's tragic take on Lex Luthor as the archenemy of Superman he was to become. In this way, Superman & Lois repeats the same plot device previously explored in Smallville to create a similar effect.
Smallville began with Clark and Lex as friends after Clark saves Lex from drowning, with Lex gradually moving toward being the villain he's known to be. Though Lex became a much darker character as Smallville progressed, he was still a long way from becoming a villain in season 4, with "Onyx" literally revealing the evildoer within him. The new Lex was fully aware of how evil he was, proudly proclaiming himself to be "the real Lex" and that "I am the villain of this story".
Unlike Lex, it's never been ambiguous that Ally is a villainess on Superman & Lois, but the show has taken its own scenic route to the reveal of Ally as the big bad of season 2. With Ally having achieved her goal, she'll also finally be shown in her complete antagonistic form. Whether that entails Ally becoming the energy-draining villain Parasite in her merged form or something else altogether will remain up in the air until Superman & Lois returns.
Superman & Lois has paid tribute to every iteration of the Last Son of Krypton in some way, so it's not surprising that the show would do the same for Smallville. However, the particular way its doing so is quite unexpected in both flipping the reveal of a future villain but still reaching the same place in the end within the two stories being told. Ally Allston might have traveled the opposite path to challenge the Man of Steel on Superman & Lois, but like Lex's journey to becoming Superman's villain on Smallville, she arrived there in a way that will reveal the sinister menace that has been hidden beneath for so long.
Superman & Lois season 2 returns on May 31 on the CW on May 31.