On Sunday night, The Walking Dead returned to kick off the back half of Season 7 with the midseason premiere Rock in the Road. The episode was directed by makeup effects artist and executive producer Greg Nicotero, who has been with the show since the beginning, and has, at times, used his position on the show to pay homage to his very first professional gig, on George A. Romero's zombie classic Day of the Dead, where he worked as an assistant to the legendary Tom Savini and made his acting debut as Private Johnson. During this past Sunday night's episode, many fans noticed that he paid tribute to Day of the Dead once again by revealing a zombie that has come to be known as "Dr. Tongue."

For fans who follow Greg Nicotero's Instagram, you likely knew this was coming for quite some time. When production wrapped on the entire season back in late November, Greg Nicotero shared a brief behind-the-scenes video on Instagram that featured the Dr. Tongue zombie, but he wouldn't specify when this zombie would appear this season. We got our answer during Sunday's episode, when he was seen leaning against one of The Kingdom walls. While this zombie didn't play a pivotal role in the story, this isn't the first time Greg Nicotero has paid tribute to one of the Day of the Dead zombies.

RELATED: The Walking Dead Season 11 Part One Finale Was a Secret Villain Origin Story

In the penultimate Season 4 episode Us, many fans noticed that the zombie affectionately known as "Bub," popped up as one of the many zombies that Glenn Rhee (Steven Yeun) and Tara Chambler (Alanna Masterson) had to fend off during a scene in a train tunnel. In Day of the Dead, Bub, played by Sherman Howard, wasn't you're typical zombie. Despite being undead, he actually remembered parts of his past life and could be taught how to perform basic tasks like listening to music. As for Dr. Tongue, he had the special distinction of being the first zombie shown on screen during Day of the Dead.

Greg Nicotero has also paid tribute to other classic zombies such as the Plaid Shirt Zombie in the original Dawn of the Dead, the mud zombie from Lucio Fulci's Zombie and a reference to Jack Goodman's zombie corpse from An American Werewolf in London. With seven more episodes left this season, it remains to be seen if Greg Nicotero has any other plans to bring some more iconic zombies into The Walking Dead universe. With seemingly no end in sight to the show, which has already been renewed for Season 8, there could be countless more zombie tributes in the future.

This season continues on Sunday, February 19 with the episode New Best Friends, airing at 9 PM ET on AMC. The very end of Rock in the Road showed Rick (Andrew Lincoln) and his crew being ambushed by a brand new group of survivors, who we'll get to meet in this new episode. We've already seen in the preview that Rick is trying to get them to join his fight against The Saviors, although it remains to be seen if they can be trusted. While we wait for more on this week's episode of The Walking Dead, take a look at this video Greg Nicotero sent out from the set featuring Dr. Tonuge, along with another photo from the set and a glimpse at the original Dr. Tongue from Day of the Dead.

Day of the Dead and Walking Dead