The Walking Dead: Daryl Dixon executive producer Greg Nicotero has explained season 2’s new zombie variants, offering insight into the upcoming threats Daryl (Norman Reedus) and Carol (Melissa McBride) are about to face. Daryl Dixon season 2 promises a more action-packed storyline, with Daryl continuing to fight against the Pouvoir as Carol takes a plane to France in hopes of tracking him down. The trailers have also teased the return of zombie variants, including the speedier variety seen in season 1, alongside new bioluminescent Walkers hiding in sewer tunnels.

Speaking with Entertainment Weekly, Nicotero revealed both bioluminescent and fast zombies, now called “ampers,” in Daryl Dixon season 2 have a majority of practical effects bringing them to life. The executive producer explained how LED lights were used for the glowing new zombies, which included having just two minutes to film certain scenes with various other light fixtures. He also explained the use of black contact lenses for ampers moving forward, using ’90s horror techniques to differentiate them. Check out what Nicotero had to say below:

During the strike, I came back to the States last year, and we were talking about the bioluminescent zombies. And 70 percent of that was practical effects. We had LED lights, and we also had this black light wildfire system where we would paint the backside of silicone prosthetics with a black light-activated bioluminescent paint. And if you watch the outtakes of that scene, you’ll literally see my team standing there with black lights right on the zombie’s faces. A lot of what VFX did was augment, by taking a lot of the bioluminescence and spreading it up the walls of the cave.

We did stuff where we were able to make the inside of the mouth glow. So a lot of it was just hiding stuff, not only in the wardrobe, but then underneath the skin, painting the silicone appliances from underneath, painting some stuff on top. And then you knew that once you would charge it right before the take, you would have probably 120 seconds of really strong interactive light before it started to fade. So there was a lot of running in, and charging it, and coming out, and then VFX just sort of amped it up.

Now we have a better indication in season 2 of how these ampers play a really important part in Genet’s [Anne Charrier] quest for power. We wanted to make sure that they looked different, so we went with black contact lenses. The inspiration was some stuff that we did on The Faculty , and then Scanners where you see these veins kind of traveling underneath the skin. And that was something that I really, really wanted to do, which was sort of redefine and play into one thing that we never play into on The Walking Dead , which is the idea that these zombies are fast.

What The New Zombie Variants Mean For Daryl Dixon Season 2

France Is About To Get Much More Dangerous

Daryl Dixon season 1 ended by revealing the Pouvoir were creating zombie variants across France, seemingly as a way to garner control over the country by instilling fear in its populace. This idea will likely keep being explored in season 2, especially now that bioluminescent zombies have been added to the mix. However, the fast zombies and those with acidic blood are still going to be core threats, especially as Daryl keeps trying to protect Isabelle (Clémence Poésy) and Laurent (Louis Puech Scigliuzzi) from getting into the villainous group’s hands.

Since there’s at least one new variant appearing in season 2, the cast of Daryl Dixon will need to maintain vigilance as they continue their fight against the Pouvoir. This will be most difficult for Carol, whose arrival in France will likely precede her knowledge that fast or acid-blooded Walkers even exist. Since the newest trailer hinted at conflict that gets one of her traveling partners killed, she may end up encountering some variants before she’s able to meet up with Daryl and learn what’s going on throughout the country.

Our Take On Daryl Dixon Season 2’s New Walker Variants

Zombies Are Made A Bigger Threat Because Of Them

The use of more zombie variants in Daryl Dixon season 2 helps keep zombies a core threat, making France one of the most dangerous countries in The Walking Dead universe. With a new variant already confirmed, there are likely even more surprising zombie-related developments in store as Daryl’s journey continues and Carol’s begins. Since there’s likely plenty of secrets the show hasn’t revealed just yet, season 2 could provide the most dangerous zombies ever seen in the franchise so far.