After all this time, The Walking Dead fans are still curious to find out what started the zombie apocalypse that has plagued the Earth for the last decade. The viral outbreak has spread from The Walking Dead onto spinoffs such as Fear the Walking Dead, The Walking Dead: World Beyond, as well as the upcoming Rick Grimes movies, the Carol & Daryl spinoff, and the upcoming anthology series. And while the series has teased just what caused the zombie outbreak in the first season, with the group traveling to the CDC headquarters to learn just why the dead are wreaking havoc, they still didn't learn why.
Things change when they get to the Center for Disease Control and Prevention in Atlanta and learn that there isn't any hope of stopping the continued creation of more zombies. That's because everyone is already infected. Now creator Robert Kirkman has revealed how that happened.
The writer of the comic of The Walking Dead and longtime producer of the AMC TV show said the zombie outbreak occurred because of a "space spore" when asked on Twitter, which is likely another homage to the godfather of the zombie-horror genre George A. Romero. In his classic film Night of the Living Dead, scientists speculated the creation of zombies could have been caused by a space prove to Venus bringing back radiation with unintended effects.
Before their book became The Walking Dead, Kirkman and original series artist Tony Moore pitched a 1960s-set continuation of Night of the Living Dead. Another tie to the extraterrestrial: when pitching The Walking Dead to Image Comics executives, Kirkman had to lie by claiming the apocalypse was caused by space aliens using zombies to weaken the world's infrastructure before invading.
Space spore.— Robert Kirkman (@RobertKirkman) January 22, 2020
Kirkman toyed with aliens again in a non-canon bonus ending for The Walking Dead #75 inspired by his fabricated origin story. According to a laser sword-wielding Michonne, an unknown alien civilization caused the dead to come back to life and attack humans, with the survivors being turned into a slave race to harvest water the aliens used as currency.
"Maybe years after it’s all over I’ll just casually mention it in an interview. That seems like a very J.K. Rowling thing to do," Kirkman said when asked about the origin of the zombie virus during a 2018 Q&A on Tumblr. "It couldn’t be less important to the story and the lives of these characters. It would be completely out of place in the story. Honestly if a scientist from Washington came to the character and told them what happened the characters would just shrug and say 'Oh… okay…' it wouldn’t change their lives at all… and… I’ve said too much."
"As far as actually trying to solve the thing, I’ve always thought that one of the best things about this show is that it’s not about scientists and it’s not about people that would take that on as a task – because I feel like that’s unrelatable," Kirkman said at San Diego Comic-Con 2017. "I think if there were a zombie apocalypse, I don’t know that there’s maybe five people in this room that would have that job. To go off and try to solve this would be a boring show, so definitely not."