I know predicting what will happen on Rick and Morty is often intentionally impossible. But here’s the thing: it’s also a whole lot of fun. Especially when Adult Swim pairs a cryptic season six promo referencing the show’s most famous “villain” with an unexplained countdown and a mysterious event called “Wormageddon.” Together they promise Evil Morty left behind a farewell present for his grandfather, a biological weapon that could mean the end of every Rick Sanchez and his grandson.

Rick and Morty‘s season five finale answered the show’s biggest questions. We learned Rick’s “crybaby backstory” and saw the culmination of Evil Morty’s plan. Evil Morty knew about the Central Finite Curve, which he called “an infinite crib built around an infinite f***ing baby.” It walls off the infinite number of universes where Rick is the smartest person from all the other worlds. That way every version of him—especially the “Rickest Rick,” Rick C-137—can do whatever they want without consequence.

Evil Morty needed to complete his scan of Rick’s brain so he could escape the Central Finite Curve. Once he had that information he left to live in a multiverse free of his grandfather’s tyranny. But before he did he killed a whole lot of Ricks and a whole lot of Mortys. Evil Morty hacked the entire Citadel of Ricks portal gun fluid. Anyone who tried to portal out of the Citadel died a brutal death before the institution exploded moments after Evil Morty left.

Evil Morty with an eyepatch stands in front of a shocked Rick and Morty
Adult Swim

We know why Evil Morty had no qualms about killing his own kind, though. Earlier in the episode he revealed Ricks are attached to Morty’s infinitely through “his weakness and our forgiveness.” Ricks need Mortys so much—and so often—the Citadel ultimately became a “Morty market.” Ricks even went from manipulating Beth and Jerry into getting together to birth Mortys naturally to creating Mortys in a lab. Evil Morty was so disgusted by his fellow kind he couldn’t even muster up hate for them. They’re just pawns “bred” for a terrible purpose – to enable Ricks.

Evil Morty seemingly left all of that behind when he broke through the Central Finite Curve and the Citadel exploded. But a short new Rick and Morty teaser, titled “A Citadel Secret,” reveals the series isn’t done with either. It opens on a mysterious giant egg inside one of the show’s signature cryogenic tubs. The egg is nefarious on its own, but after a few peaceful seconds the Citadel—which Evil Morty controlled for years—starts to blow up as Evil Morty’s signature music plays.

This promo not only takes place during the season five finale, the unmistakable music cue ties Evil Morty to the strange egg. An egg he left behind on a space station he turned into a Rick and Morty killing machine.

Adult Swim

That little teaser would be exciting enough on its own, but the official Rick and Morty website is in on the mysterious fun, too. It currently has an unexplained countdown set to go off at 7:00 a.m. PT on August 18. The site also lists an upcoming event known only as “Wormageddon.” That’s a whole lot of teasing for something that feels big and sinister. So what could it be? Once again we turn to Evil Morty for the answers.

The Central Finite Curve exists separate from the rest of the multiverse. But it still contains an infinite number of worlds. That means it still contains an infinite number of Ricks and Mortys and always will. Even though Evil Morty escaped, what’s to stop Ricks from following him? Or attacking worlds outside their own infinite subsection? And even if they do nothing, with an infinite multiverse the whole cycle of the Citadel, Morty exploitation, and Ricks being giant a-holes will repeat forever. Evil Morty only got away and killed a meaningless number of enemies. He didn’t actually stop Ricks.

To do that you must destroy the Central Finite Curve and everyone within it forever. And the show already provided a way to make that armageddon possible – worms.

Adult Swim

Rick and Morty‘s fourth episode of season three introduced The Vindicators. (Who just got their own prequel digital spinoff series.) But it opened with Morty trying to capture a bunch of dangerous little blue alien worms called semosites. “If their DNA gets into Earth’s food chain our entire species could be sterilized,” said Rick. When Morty asked why they didn’t just destroy them, Rick said it’s because he uses semosites to do just that – sterilize an entire species.

What better way to ensure the end of all Ricks and all Mortys forever than by leaving behind the mother of all semosites, one that could sterilize the Central Finite Curve? That would mean no more reproduction, which means no more Mortys, and ultimately no more Ricks. That would certainly qualify as “Wormageddon,” the final masterstroke in Evil Morty’s plan.

Makes sense, right? Obviously we think so. But will it prove to be right? Who cares! When it comes to Rick and Morty it’s fun to try and predict the unpredictable.

Mikey Walsh is a staff writer at Nerdist. You can follow him on Twitter at  @burgermike. And also anywhere someone is ranking the Targaryen kings.