When the Marvel Zombies made their debut in Marvel’s What If…?, their greatest threat was Thanos, but in the comics, they became the new Galactus.
In Marvel’s What If…?, the fan-favorite Marvel Zombies made their transition from comics to the screen but with a few significant differences. Although both versions follow a similar storyline as the dwindling few heroes struggle to survive while trying to cure the virus that has overtaken their world, the episodes’ ending went in a completely different direction with a familiar threat making itself known instead of Earth’s Hungriest Heroes taking their mission into space like in the comics.
In Marvel Zombies by Robert Kirkman and Sean Phillips, the Marvel heroes from a parallel dimension have an infected hero appear from an unknown world who turns the Avengers, beginning an invasion that devours the non-powered population while turning any superhuman into ravenous yet intelligent monsters. In Marvel’s What If…Zombies?, a version of the MCU is under attack by a zombie virus brought from the Quantum Zone by Hank Pym in his doomed attempt to save his wife Janet. Heroes and villains connected to the arrival of Thanos quickly learn of the fate that has befallen this Earth as the survivors struggle with the horrors that used to be their friends but also the decisions of others during this dark time.