Ever since The Walking Dead comic book debuted in October 2003, fans have been wondering what exactly caused the series' zombie outbreak. The Walking Dead series creator Robert Kirkman has consistently said that the origin of the zombie virus wouldn't be explained in the comics, insisting that its origin was ultimately pointless to the story being told. Despite this, Kirkman has said that he himself knows what caused the virus, and that he may reveal it randomly at some point in a future interview. Well, Kirkman may have finally revealed The Walking Dead zombie virus origin, though it's possible he's just joking.
On Twitter, a fan asked Kirkman what caused the zombies in The Walking Dead, and he responded, "Space spore." What's interesting about this answer is that Kirkman's pitch for The Walking Dead series to Image Comics said that aliens were behind the zombies, using the undead to "weaken the world's infrastructure" before invading. Kirkman had no intention of going through with the alien invasion pitch (it was just a lie to get the series approved), so his "Space spore" explanation could just be an extension of that joke.
While the origin of the zombie virus in The Walking Dead may not be that interesting to Kirkman himself, it's understandable why fans want answers. The Walking Dead is a massive media franchise after all, having extended to basically every form of media imaginable, including video games.
Telltale's The Walking Dead games have been huge hits, and there's also a popular augmented reality Walking Dead game available as well. Other Walking Dead video game projects haven't had quite the same success, though one recent release is rather impressive.
The Walking Dead: Saints and Sinners VR game just launched for PC-powered VR headsets and is earning decent reviews. If nothing else, it shows that there is still a lot more quality content to mine from The Walking Dead universe, so even with the comic book series over and the AMC TV series no longer at the height of its popularity, fans should be able to look forward to Walking Dead content for years to come.
Whether or not any of this Walking Dead content ever provides a proper reveal for the zombie virus remains to be seen, however. For now, fans may have to be satisfied by Robert Kirkman's "space spore" answer until they hear something different.