Andrew Lincoln and Chandler Riggs star in “The Walking Dead”

Not long ago, vampires were all the rage on television and the big screen. Now, zombies have taken over and they seem to be unstoppable.

Hailed as an "honest-to-god phenomenon" by Variety, few television shows have sparked the same sort of "fandemonium" as AMC's "The Walking Dead," which returns Sunday, Oct. 11. The show is based on the comic book series of the same name by Robert Kirkman, Tony Moore and Charlie Adlard. Season 6 of the series will once again follow the survivors of a zombie apocalypse as they battle the undead and each other. After last year's cliffhanger season finale, fans have been champing at the bit for the show's return.

With nearly 16 million viewers, the season 5 finale broke ratings records for the series. Rick (Andrew Lincoln, "This Life") and his group had been taken in by the people of Alexandria, a "safe" community fenced off from zombies, near Washington, D.C. However, they remained skeptical of the Alexandria residents and it appeared that a major power shift was about to take place at the end of the last season.

AMC's official trailer for the new season alludes to such a power shift, with tense scenes between Rick and the other residents, hordes of zombies -- or "walkers," as they're known in the series -- and banter between new arrival Morgan (Lennie James, "Jericho") and Alexandria leader Deanna (Tovah Feldshuh, "Law & Order").

However, according to executive producer and showrunner Scott M. Gimple, fans may not want to put too much stock in what they think might happen. During a panel for "The Walking Dead" at this year's San Diego Comic-Con, he hinted: "We sometimes play with the truth in trailers ... just to maintain the experience for everybody." Interesting ...

Gimple went on to say that Rick faces challenges in season 6 because of what went down in the season finale (don't worry, you won't find any spoilers here). “Things might not be as they seem, but Rick absolutely has to deal with the fact that things went down with Reg [Steve Coulter] and with Pete [Corey Brill] and all of these people who might have been following him into the bowels of hell are maybe looking at him a little differently.”

Those willing to follow Rick into zombie-populated hell include fan favorites Norman Reedus ("The Boondock Saints," 1999) as Daryl, Steven Yeun ("I Origins," 2014) as Glenn, Lauren Cohan ("Supernatural") as Maggie, Danai Gurira ("Treme") as Michonne, Melissa McBride ("Living Proof," 2008) as Carol, Chandler Riggs ("The Wronged Man," 2010) as Carl, Sonequa Martin-Green ("Toe to Toe," 2009) as Sasha, and Michael Cudlitz ("Southland") as Abraham.

These characters have formed the core of the series so far, and fans are no doubt hoping all of them will make it through another season, though you never can be too sure with "TWD."

Melissa McBride as seen in “The Walking Dead”

Since the season 5 finale, people have been buzzing about season 6, especially the addition of James, whose character has been tracking Rick since saving him from a walker at the very beginning of season 1. The actor has been acclaimed for his portrayal, even though he's only appeared in a few episodes in seasons 1, 3 and 5.

Also new in season 6 are Merritt Wever ("Nurse Jackie") as Dr. Denise Cloyd, Ethan Embry ("Grace and Frankie") as Alexandria resident Carter, and Corey Hawkins ("Straight Outta Compton," 2015) as supply runner Heath. News also recently broke that Xander Berkeley ("24") will join the cast for the latter half of season 6. While many people have speculated that he will play Negan -- a villain from the comic series -- others insist this will not be the case. He will, however, play a major villain.

The mysterious and seemingly ruthless survivor group known as The Wolves will also play a part in the upcoming season, though Gimple teased that it may be in a way viewers won't expect.

By the way, fans of the TV show hoping to get the scoop on what's going to happen next need not turn to the comics. Although many of the characters, settings and situations follow the decade-long comic series, the writers of the AMC drama don't always go by the book and have been known to take liberties with the source material. In fact, one of the TV show's most popular characters, Daryl, doesn't even appear in the comic.

The blend of comic and original material is obviously working for the series, which has ranked as not only the top cable drama, but the top drama overall in the coveted 18 to 49 demographic during its fourth and fifth seasons. The hit show has also spawned a groundbreaking mobile game entitled "The Walking Dead: No Man's Land," scheduled for an October release. Designed for touch screen devices, the game features the voice of Reedus as players strategize to survive in a post-apocalyptic world.

The wait is almost over, folks. "The Walking Dead" bursts back onto TV Sunday, Oct. 11, on AMC.