Did "Crisis on Earth-X Part 2" Drop a 'Doom Patrol' Easter Egg?

head there to stop their evil counterparts. While the fight between them doesn't go particularly [...]

crisis on earth x doom patrol
(Photo: Warner Bros. TV/The CW)

This year's Arrowverse crossover, "Crisis on Earth-X," has no shortage of superheroes to take on the Earth-X Nazi villains, but there's no shortage of Easter eggs either -- including a Doom Patrol reference.

Spoilers for the second hour of "Crisis on Earth-X" below!

In the second hour of tonight's crossover, the heroes discover that the Earth-X Nazis' have broken into a lab looking for something so Supergirl (Melissa Benoist,) Green Arrow (Stephen Amell,) and The Flash (Grant Gustin) head there to stop their evil counterparts. While the fight between them doesn't go particularly well, the sign on the building may be familiar to some DC Comics fans: Dayton Optical Systems might just be a sly reference to Doom Patrol character Mento, aka Steve Dayton.

In the Doom Patrol comics, Dayton is one of the world's richest men, and he builds himself a helmet that enhances his mental abilities. Calling himself Mento, Dayton attempts to impress a member of Doom Patrol, Elasti-Girl. His plan works. They pair marry and adopt Beast Boy, but their happiness is short-lived. Elasti-Girl is killed, leading Mento to hunt for her killers, General Zahl and Madame Rouge.

Coincidentally, there's something red that the Earth-X villains are hunting for at Dayton Optical Systems in tonight's crossover. They're there to retrieve something called The Prism. Harry reveals that the item is a sublight generator of sorts, capable of carrying out a stable fusion reaction which has all kinds of horrible applications. Just what the Earth-X villains plan to do with it? Keep watching "Crisis on Earth-X" to find out, because whatever it is it can't be good, for Earth-X or Earth-1.

"Crisis on Earth-X" is a four-hour event that will air on November 27th and 28th beginning at 8 p.m. and running for two hours each day; Supergirl (8 p.m. Monday), The Flash (8 p.m. Tuesday) and Legends of Tomorrow (9 p.m. Tuesday) will remain in their normal time slots but Arrow will move from Thursday to a 9 p.m. Monday placement for the week.