What, exactly, did The Walking Dead want to leave us with? Is it revealing images of Commonwealth destruction? A fan favorite character in peril? The return of Rick Grimes?!?!? The answer turns out to be “none of the above.” Check out the trailer below to see the ominous closing moments. “I’ve heard stories of walkers that can climb walls and open doors. I was never sure if they were just stories,” Aaron (Ross Marquand) says. Well, we’re pretty sure they’re not stories because that zombie definitely just pulled its rancid body up over a fence. Zombies can climb now! After the trailer dropped at this year’s San Diego Comic-Con, The Walking Dead Twitter account made quite a meal of the reveal as well. Simply put: there is a lot of zombie storytelling still on the docket for AMC and TWD Universe czar Scott Gimple to pursue. After more than 20 seasons of zombie storytelling, how can Gimple and company possible keep things fresh? The answer, it seems, lies in evolving the physiology of the zombies themselves. Though the “rules” of how an undead corpse monster operates vary from franchise to franchise, the tenets of The Walking Dead‘s walkers have always remain consistent. As first depicted in Robert Kirkman’s comic series, TWD‘s zombies have operated under what one might call the Classic Romero Rules from George A. Romero’s first two films. These zombies are weak, slow, unintelligent, and completely lacking in motivation to do anything other than eat. This doesn’t make the singular zombie a particularly acute threat but it does make the collective population of zombies in The Walking Dead‘s world a dangerous environmental hazard. There are simply so many of these guys and none of them will ever stop their pursuit of flesh. While that has made for some effective horror storytelling over the years for The Walking Dead, signs have started to pop up that the franchise wanted to try something different with its zombies even before the season 11 trailer premiered. The second TWD spinoff, The Walking Dead: World Beyond was not widely watched (and truthfully also not very good) but it just happened to feature a truly revolutionary moment in TWD zombie lore. In a post-credits scene set in a French lab and featuring none of the show’s central characters, it is intimated that French doctors had something to do with creating (or maybe exacerbating) the zombie virus. You can read all about the scene here but the TL;DR of it is that the concept of “variant cohorts” of the virus are mentioned. Then, when one unnamed character kills another unnamed character, that character reanimates almost immediately and her newly zombified form runs at a locked door with shocking speed and intensity. Therefore variant cohorts of the virus are likely mutations that lead to different behavior in zombies…behavior like, say, opening doors or climbing fences. The aforementioned zombie master himself, Romero, opted to let his zombies evolve in his films as well. Latter day Romero movies like Day of the Dead and Land of the Dead featured zombies learning new behaviors and in some cases even becoming organized. It now seems likely that The Walking Dead‘s zombies are set to evolve in their own way as well. But they better evolve quickly as there are many new stories to come and only so many fences to climb.