WARNING: The following contains spoilers for What If...? Season 1, Episode 3, "What If... the World Lost Its Mightiest Heroes?," now streaming on Disney+.

Comics, as a medium, often play fast and loose with the laws of physics. It’s all in good fun these days, and the medium has grown considerably better about it than in earlier eras, but it’s always been a part of the fabric. It's also led fans down some very weird rabbit holes, including one theory from the Marvel Cinematic Universe fandom that has resurfaced in the franchise's latest installment, What If...?.

Dubbed the “Thanus theory,” this idea spent years building momentum before the release of Avengers: Endgame, positing that Thanos could be defeated by a shrunken Ant-Man crawling up a bodily orifice and expanding. The MCU, always aware of what its fanbase is talking about, paid homage to the trend in What If…? Season 1, Episode 3, “What If… The World Lost Its Mightiest Heroes?”

RELATED: What If...? Finally Gives Loki His Heart's Desire - For Now

The theory itself started somewhere on Reddit in 2017, then moved to different social media platforms as Thanos’ appearance in Avengers: Infinity War and Endgame grew closer. It originally held that the Hulk could use Ant-Man’s suit to enter Thanos through the mouth and expand in various locations throughout his anatomy. Soon enough, the theory had dropped the Hulk and just went with Ant-Man. It was gross and frankly horrific, but it had an irrefutable logic, and with half the universe on the line, all options were on the table. The Thanus theory was simply too ghoulishly practical to ignore.

The concept took hold very quickly, particularly in the hype-laden weeks before Endgame. Fans made memes and suggestive images implying not only that Ant-Man could do this, but that he should. It fed into the movie’s more straightforward speculation of how the surviving Avengers could possibly stop a villain who controlled reality, and – as juvenile as it was – picked up a great deal of legitimate support. Endgame quite sensibly went in another direction, and the results speak for themselves, but the moment remained.

RELATED: MCU Theory: Winter Soldier Killed [Spoiler] in What If...? Episode 3's Reality

What If…? wasn’t quite ready to dive into the toilet humor implications of the Thanus theory, but it found a way to nod to the trend regardless. “What If... the World Lost Its Mightiest Heroes?” concerns Hank Pym’s assassination of the original Avengers before Nick Fury has a chance to recruit them. In at least three instances, he does so in a manner similar to that prescribed by the Thanus theory. Iron Man, Hawkeye and the Incredible Hulk are all killed by Pym shrinking down, entering their bodies, and causing lethal amounts of damage in a very short time.

The Hulk, in particular, tips the MCU’s hand as far as its inspiration goes. Presumably unable to damage Bruce Banner’s gamma-irradiated cells, Pym launches a Pym particles disk at the Hulk’s heart. In the episode’s most gruesome moment, this makes his heart grow until the Hulk himself explodes. The fact that the Thanus theories began with the Hulk, and the overtly disturbing image of watching him die in more or less the same way Ant-Man could've killed the Mad Titan, goes beyond suggestion into the realm of homage.

Every franchise consists of an exchange with its creators and its fans, and while a given movie or series shouldn’t give in to mob rule when it comes to storytelling, many franchises still find ways to acknowledge their audience’s creative contributions. The Thanus theory is conceptually gross, but it also represents a moment when fans expressed their avid enthusiasm for an upcoming MCU project in a unique and memorable way. With Hank Pym’s rampage, What If…? found the perfect means to honor that excitement.

To see the closest thing to the Thanus theory in action, watch Episode 3 of What If...?, streaming now on Disney+.

KEEP READING: What If...? Season 1, Episode 3, 'What If... The World Lost Its Mightiest Heroes,' Recap & Spoilers