Jesus was part of a search party with Daryl (Norman Reedus) and Aaron (Ross Marquand) looking for Eugene (Josh McDermitt), who was hiding from the herd in a barn because his dislocated knee was too injured to try to run with Rosita (Christian Serratos). Jesus, Daryl and Aaron noticed the herd behaving in ways they'd never seen walkers behave, and when they found Eugene, he said the herd had been looking for him and he'd heard them talking, saying things like "they did surgery on a grape." The other guys were skeptical, but Eugene made a compelling case for the walkers evolving. Since the way to kill a walker is by destroying the brain, that means the brain isn't exactly dead. And since it's not exactly dead, it can change. Maybe the walkers are starting to remember stuff or learn stuff. This theory would be disproven by the end of the episode, but it's an interesting one! Maybe it can be explored if there's a Walking Dead spin-off set in the future. The Walking Dead 2049.