It’s hard to remember now, but there was once a time before superheroes. Before Stan Lee, Jack Kirby, and Steve Ditko created the colorful costumed crimefighters that now dominate page and screen, Marvel used to publish all kinds of stories across a plethora of genres, featuring lots and lots of monsters.

But never like this: Monsters Unleashed, Marvel’s next big crossover event, will feature a massive, simultaneous attack on the Marvel Universe by all of these monsters. That’s right, all of them.

“If there ever were a monster who stood 10 stories high or taller and created mayhem in the Marvel Universe over last several decades, they’re gonna be in the story,” Marvel editor-in-chief Axel Alonso tells EW.

“Our goal is to cram as many mammoth monsters of Marvel into Monsters Unleashed as will fit on the page,” editor Mark Paniccia adds. “If you’ve got a personal favorite, chances are very good you’ll see them causing some mayhem in this series. And if you’re worried we’ll forget one, don’t be afraid to tweet at us @Marvel using the hashtag #MonstersUnleashed.”

As seen above in the promotional image by Steve McNiven, that lineup includes not only classically villainous monsters like Fin Fang Foom, but also monsters like Devil Dinosaur and Groot who have fought on the side of good (check out that shot of Groot facing off against his Guardians of the Galaxy teammate Rocket Raccoon). Alonso and writer Cullen Bunn are staying relatively mum on specific story details like that, but according to them, the premise is relatively straightforward.

“It’s an all hands on deck situation,” Bunn says. “Imagine something like the Hulk, only much bigger. With the destructive force those creatures have, the heroes will have to mobilize much more quickly. The heroes find themselves very quickly in a situation where they have no downtime, they have no chance to take a breath. They’re moving constantly against what are essentially cataclysmic threats over and over again.”

In other words, Monsters Unleashed is something like Marvel’s version of Pacific Rim, except instead of giant robots fighting monsters, it’s every single Marvel superhero – right on down to more street-level crimefighters like Deadpool and Luke Cage. The Marvel heroes have been divided by recent conflicts like Civil War II, but this cataclysmic threat will force them to put aside their differences and unite. The advantage of that is readers unfamiliar with recent Marvel continuity can easily jump in with no prior knowledge of all the recent ins and outs. There won’t even be that many branded tie-in issues, according to Alonso; just a few calculated choices to be finalized later. In fact, the event and its monsters harken back to an earlier era of Marvel.

“Jack Kirby, Steve Ditko, Don Heck, and Herb Trimpe — all of these guys created incredible monsters that we remember from my childhood,” Alonso says. “They’re the equivalent of those Ray Harryhausen-type monsters, those rubber suits that thrill us. To see them coming back, and to take them seriously, it’s a lot of fun.”

Artists like Kirby were known for their innovative use of splash pages and wide-scale action, and Monsters Unleashed will feature plenty of that style in its own art. Each issue is illustrated by a different superstar Marvel artist, many of whom are veterans of past crossover events: McNiven, Leinil Yu, Adam Kubert, Salvador Larroca, and Greg Land. In addition to giving various interpretations of the monsters at hand, the use of different artists will also speed up the series’ schedule. The five issues of Monsters Unleashed will ship bi-weekly, starting in January.