SPOILER WARNING: This article contains major spoilers for "Crisis on Earth-X, Part 1," the first episode of this year's Arrowverse crossover.
"Crisis on Earth-X," this year's four-show Arrowverse crossover, may have just introduced Barry and Iris' future daughter. In the first part of the crossover, Barry had a rather puzzling exchange with a waitress, who seemed overexcited to see the two exchange their vows.
As Barry waited for his bride to walk down the aisle, a waitress approached him from behind. "Sparkling?" she asked breathlessly, making him turn around to face her. "Excuse me?" he responded.
"I just thought you might be a little parched," she said with a smile. "Big day jitters and all. You're getting married! Today."
"Yeah, I am. Today," he agreed as she smiled blithely at him. She shook herself out of her reprieve to ask, "Sparkling water? I have lemon, I have lime..."
When he turned her down politely, she told him, "I'm really excited to be here. I mean, at a wedding! Any wedding! It just so happens to be your wedding."
"You love weddings?" he asked in return, to which she said, "I really do. Actually, I don't know, I just feel like this is going to be one for the ages. I'm really happy I got to see it."
As she said this, he frowned. "Have we met?" She shook her head emphatically. "No! No, I'm a complete and total stranger. Good luck up there," she said, taking his arm. "Just remember to say, 'I do.'" With that, she turned and walked away, leaving Barry to stare after her quizzically.
In a crossover event so packed with characters, an extensive scene like the one above simply can't be a throwaway bit. Considering the length of time they spoke and Barry's semi-recognition of her, it seems as though she will somehow be important to him. Combined with the fact that The Flash is also no stranger to time travel, the crossover episode may have introduced Barry's future daughter with Iris.
Of course, there is precedence for this. In the comics, Barry and Iris had a daughter named Dawn Allen after they retired to the 30th century. Both she and her twin brother Don inherited their father's speed. They never met their father, who died before their birth in the events of Crisis on Infinite Earths, but soon followed in his footsteps to become Speed Force heroes known as the Tornado Twins.
This year’s four-part crossover “Crisis on Earth-X” will air across two nights, beginning Monday, Nov. 27 with Supergirl and Arrow (on a special night for one week only) and concluding Tuesday, Nov. 28 with The Flash and Legends of Tomorrow.