In an episode that was so packed that few, if any, moments were spared on something that will not pay off down the line, it was a bit jarring to see about 30 seconds of tonight's "Crisis on Earth-X" focusing on a young girl bringing Barry sparkling water.
She is adorkably awkward, played by Jessica Parker Kennedy, and seems a little too thrilled to be spending time at a stranger's wedding.
Her physical appearance -- some fans say she somewhat resembles what a baby from Candice Patton and Grant Gustin might look like -- has led many to assume that she will have a significant role going forward on The Flash, if not in the crossover itself.
The two most popular candidates for who she might be? Dawn Allen and Jenni Ognats.
That would be the daughter and granddaughter, respectively, of Barry and Iris in the comics.
In the comics, Dawn Allen is the sister of Don Allen, and together they make up the super-speedster duo known as the Tornado Twins. Conceived toward the end of Barry's life (well, his pre-Crisis on Infinite Earths life. He came back later), the pair lived in the 30th Century and were a part of the Legion of Super-Heroes.
Because of Barry's death in the Crisis, they never knew their father and were often depicted as jealous of Wally West, who got to have Barry as a kind of surrogate dad. This blew over when Wally, time-displaced after a battle with Savitar, ended up in their time and they got to know him as a person.
The absence of a second, male figure (at least at this point in the story) may point to Ognats -- the Legionnaire known as XS. In the comics, she is depicted as black (at a time when Iris and Barry were both white), and so were the Tornado Twins), and so a Flash fan might take one look at Kennedy and think "XS" more quickly than her mother, Dawn.
Either way, if her identity were revealed it could prove problematic for the blushing bride: in tonight's episode, Iris dismisses the idea of having kids right away, and during a recent interview on the set of The Flash, she said the same to reporters.
"I think it's too early to start talking about kids," Patton said. "Let's just get them married first, and get through aliens, and world domination, and all that good stuff."
The connections between those speedsters and the Legion of Super-Heroes is interesting, since the Legion will play a significant role on Supergirl this season.
While Don and Dawn have been around since the '60s, Jenni first appeared in 1994, apparently created as a result of the timeline damage from Zero Hour.
"Crisis on Earth-X" began tonight at 8 p.m. ET/PT and will run for two hours per night, today and tomorrow. Unlike last year's crossover, which skewed heavily episodic and could be joined at more or less any point, "Crisis on Earth-X" is shot like a movie, and if you missed tonight's episode of Supergirl and Arrow, your best bet may be to wait until the episodes are on The CW app tonight or tomorrow morning so that you can get caught up ahead of The Flash, which picks up the second half of the story at 8 p.m. tomorrow.