Think the zombies in The Walking Dead have lost their fear factor? Actor Norman Reedus says The Walking Dead season 4 will introduce a new threat from the zombies.

“They’ve introduced a way to make the zombies scary again,” said Reedus when speaking to EW on their podcast this week. “They’re terrifying. The new threat is just unreal.”

While it’s not clear what the new threat is (perhaps something introduced in the comic book series by Robert Kirkman), we’ve recently realized that the human survivors have gotten pretty good at thwarting off the zombies over the past couple seasons. A new threat will certainly make them interesting and require new combat tactics, but what could the threat be? The ability to move faster? New weapons? Flight? Cars?

Reedus, who plays Daryl, added that The Walking Dead season 4 has some great writing. “The scripts this season are just amazing,” he said. “It feels like we’ve shot about three movies already. It’s super intense.”

As if that weren’t enough to get you excited, Reedus added that “the structure of the writing is a bit different. It’s so intense. These are our best scripts so far.” The structure change is due in part to the switch in show runners (Scott Gimple replaced Glen Mazzara).

Reedus certainly offered a ton of high praise for the next season of AMC’s most successful show ever, and we can’t wait for the premiere later this year.

The Walking Dead season 4 will air this fall on AMC. We expect the first trailer and the season 4, episode 1 air date to be unveiled at San Diego Comic-Con next month at the show’s annual cast panel.

Thanks, EW.