Spoilers below for anyone who hasn't watched the Supergirl episode of the "Crisis on Earth-X" crossover.
The Arrow-verse's most comprehensive mega-crossover finally kicked off tonight on The CW, and though Part 1 was a Supergirl episode, a big chunk of it was devoted to Barry and Iris' wedding, even if those nuptials were soon interrupted by Nazi doppelgängers of our main heroes. As excitingly bizarre as all that was, we were perhaps more intrigued by that awkward caterer whose non-romantic infatuation with Barry was too pronounced to be trivial. And so, taking into account everything we've seen this season, we're posing the bonkers theory that the caterer is actually Barry and Iris' daughter from the future.
Stay with us now, because it's not the most bonkers theory available. (Maybe if we thought that she was actually pre-Flashpoint Sara Diggle...) When the mysterious and unidentified caterer first walks up to Barry and offers him some sparkling water, she enters the frame out of focus before sharpening up, which was noteworthy in and of itself. Camerawork aside, she keeps her eyes locked on Barry's face the entire time she's nervously rambling about the wedding, and it all comes across in a way that makes it quite obvious she's there specifically to witness Barry getting married. Her words:
It's not like Barry is the kind of person who has lots of fans out there, even if The Flash might, and it's probably not too often that wedding caterers work ceremonies that they're personally invested in. Plus, she appears too sweet and innocent to be tied into The Thinker's grand schemes, even though that's certainly possible. No, she almost definitely has a personal objective and fascination with being there in that moment, and considering The Flash hasn't used the old time-travel trick in a while, it makes a certain amount of left-field sense that this is actually Dawn Allen, one half of the comics' Tornado Twins. Remember when post-Speed Force Barry gave his "We're gonna need more diapers," line in the premiere? She could be the payoff.
In the comics, speedster twins Dawn and Don Allen (also called the Tornado Twins) are conceived by Barry and Iris in the 30th century and are largely raised by just Iris, since the Crisis on Infinite Earths timeline took Barry out of the picture for a while. I don't expect the show's timeline to jump 900 years into the future or anything, but it's feasible that the caterer could be Dawn Allen from, say, some version of the 2046 timeline that we've already visited in the past. And that, for whatever reason, Barry isn't around anymore to rise her into adulthood, so she doesn't really remember him.
That would explain not only her unencumbered awe while talking to just him, as opposed to also having a conversation with Iris, but also why she calls herself a complete and total stranger to him. And if Barry and Iris' marriage somehow doesn't end up happening for some reason in a certain timeline -- because of Nazi doubles or some other reason-- that would be a fine explanation for why she's sure to tell him to say "I do." In a way, it would add some further oddball depth to Joe saying he wished Barry's parents were there for the wedding, since it would actually be Barry's kid watching it instead. Plus, Nora and Henry Allen can't get mentioned without invoking thoughts about Barry's own attempts to change the past, which ties in here. If all this is true, we damn sure hope Barry's offspring is better at it than he was.
To take this thought-train even further, what if Caterer-as-Dawn-Allen ends up visiting Barry and Iris' current digs for whatever reason -- possibly to confess to her time-traveling plan -- and she's so impressed with their living establishments that she's the one who first said the "This house is bitchin'" line. Stranger things have happened, probably.
This is not a perfect theory, mind you, and there are definitely loose ends this early on, as well as unanswered questions. Why doesn't Don Allen show up? Why would Dawn Allen go back to the day that the Nazis showed up, as opposed to the day that Barry and Iris actually get married, assuming they still do at some point? What if that's actually Cecile's daughter-from-the-future who has a weird crush on Barry? Until we know more, though, Dawn Allen remains a possibility, and it's the possibility that I'm hoping for the most.
The Arrow-verse's crossover event continues on The CW with a special-night episode of Arrow, followed by The Flash and Legends of Tomorrow's entries on Tuesday, November 28, starting at 8:00 p.m. ET. Zip on to our fall TV premiere schedule and our 2018 midseason schedule to see what shows you'll need to get invested in when all the CW shows are on winter hiatus.