The Walking Dead returns this weekend for more nihilistic zombie munching and machete-wielding action—but just because the show is already a huge ratings bonanza for AMC doesn't mean the channel doesn't want to drum up more viral marketing for it. To that end, they released a video of a terrifying prank this week in which "zombies" reached up through a subway grate to scare the shit out of passersby. Except it seems they freaked out NYC officials as well: "We are deeply troubled by this video," an MTA spokesperson told WPIX. "We have forwarded it to the NYPD and are also conducting our own investigation."

Permits are required for commercial shoots with actors that use public space, and the MTA says permission was not granted for the company to open up a sidewalk grate. At first, we assumed most of these "scared" people were hired extras, and this was just another Macklemore-style lie. But it's possible AMC just did a really good job of keeping a lid on the prank before releasing the final video. At least a few people did spot the zombies there at the start of last week:

Those AMC folks sure like their zombie pranks.