Enter To Win An Ultra-Rare T-Shirt From The Supergirl, The Flash, Arrow and Legends of Tomorrow Crossover

How would you like an ultra-rare t-shirt celebrating The CW's four-show "Invasion!" crossover, which launches tonight?

The CW has produced an extremely limited number of "Heroes vs. Aliens" t-shirts, featuring the stars of Supergirl, The Flash, Arrow, and DC's Legends of Tomorrow standing above what appears to be the Hall of Justice.

(The building, seen in teasers for the crossover appears to in fact be either a new or a previously-unseen STAR Labs building.)

And today, ComicBook.com has five of the t-shirts to give away.

The winners will be chosen at random from those who enter, and with fewer than 100 of these t-shirts having been made, it's likely to become a serious collector's item. We'll also throw in a ComicBook.com t-shirt to sweeten the deal, so that if you're more the "put this sucker under glass" kind of collector, you don't have to give up the shirt off your back to do it.

Arrow, The Flash, and Supergirl will cross over with DC's Legends of Tomorrow next week in "Invasion!" a three-part crossover that starts in the final moments of an episode of Supergirl and then plays through the other series. Based on the 1988 comic book event miniseries Invasion! from Keith Giffen, Bill Mantlo, Todd McFarlane, Bart Sears, and the crossover -- with its marketing title "Heroes vs. Aliens" -- will closely track the plot of that storyline: aliens will be assembled by The Dominators and descend on Earth to bring an end to the "threat" of Earth's burgeoning metahuman community.

In the comics, the Dominion were secretly hoping to build their own super-race, and as a result created a handful of new superheroes in the course of the story.

In the TV version, rather than assembling a loose alliance of dangerous alien races, the Dominators will apparently be mind-controlling the aliens that join them. That's a revelation that suggests even the heroes might be forced to take one another (or at least the alien Supergirl) on at some point in the story.

All you have to do is complete the contest form attached here, and then maybe jump into a timeship to next week to see if you won.

NEXT: The Flash, Arrow, Supergirl, Legends of Tomorrow Crossover Trailer / First Look At The Dominators / Invasion! Crossover Promo Photos / Potential The Flash Spoiler Spotted On Set / Will Joe West Die During The Invasion! Crossover?

Supergirl airs Mondays at 8 p.m. ET/PT; The Flash on Tuesdays at the same time; Arrow on Wednesdays and DC's Legends of Tomorrow on Thursdays. All four series air on The CW. The "Invasion!" crossover will air beginning November 28.