WARNING: The following contains spoilers for What If...? Season 1, Episode 5, "What If… Zombies?!" streaming now on Disney+.
When it was revealed Ultron would be created by Tony Stark and not Hank Pym in the Marvel Cinematic Universe, fans wondered if the movies would follow the dark path we've seen in the comics. It turns out, by the time Michael Douglas took on the role, his story would be more about an obsession with rescuing Janet from the Quantum Realm rather than trying to run projects that would directly compromise world safety or sate his ego. However, as "What If... Zombies?!" confirms, while the mainstream Hank doesn't seem as careless, his knack for letting his heart get the better of him definitely shapes him as the MCU's biggest liability.
This notion was first touched upon in this series, in the reality where Hank became a demented Yellowjacket and killed the Avengers. He was angry Hope joined S.H.I.E.L.D. and died, so he took out the people on Nick Fury's list as revenge, proving that Hank's inability to control his emotions was indeed dangerous. Admittedly, we did see bits of that in Ant-Man when he lashed out at S.H.I.E.L.D., hinting he could go off the rails someday.
Luckily, he was reunited with his family in the prime MCU, however, in What If...?'s zombie apocalypse we see just how risky Hank's antics can be when he lets the idea of loss and defeat take over. Obsessed with finding Janet, he makes his way to the microverse once again, but when he finds Jane, she attacks him. She's been zombified thanks to a virus, and when their ship gets back to the real world the couple attack Scott Lang and Hope, in what's essentially ground zero. Later, even Captain America gets infected, spreading the plague of the undead to the Avengers.
All of this isn't directly Hank's fault, but it once more shows what can happen when he tries to play God, operating relentlessly to get what his heart desires. He just doesn't think with his head, which is surprising for a genius scientist. This misguided passion, after all, is what led to Yellowjacket appropriating his tech in the first film, but in these alternate realities his unchecked actions result in much scarier incidents and consequences on the whole.
Sure, he might not be creating killer bots, lashing out at Janet, or acting aggressively towards other heroes and such, but his scientific conquests do come off as unhealthy. Had he let sleeping dogs lie, as tragic and painful as it is, Janet wouldn't have brought the virus out to the world.
Hank's need for control should be nipped in the bud. It's an idealistic trait that reflects why he often lost it in the comics, which foreshadows something cataclysmic to come. Of course, he's a tad more subtle and sympathetic in the main MCU, but what these episodes show is that maybe someday, in the main reality or as the multiverse fractures, Hank may concoct some wacky scheme to fix something that goes wrong. It won't be surprising, as he loves repairing broken systems, but as his track record shows, there's high probability it may do more harm than good.
What If...? releases new episodes every Wednesday on Disney+.