'Power Rangers,' Netflix and More Dominate New York Comic Con

— -- New York Comic Con wrapped on Sunday after four jam-packed days of pop culture news.

Thousands gathered from Thursday to Sunday at the Javitz Center in New York City to check out panels and events around hit shows, including "The Walking Dead" and "Stranger Things," and upcoming movies like "Power Rangers."

Netflix also had a strong showing with its Marvel shows, including a surprise appearance from a possible new villain, played by an iconic actress.

Here's a breakdown of all the big moments:

"The Defenders"

"Defenders" Assemble!

At the packed main stage Saturday evening, Marvel not only unveiled the new trailer for its upcoming Netflix series "Iron Fist," but also assembled, for the first time, all of "The Defenders." There were more surprises: notably, Sigourney Weaver has joined the Marvel family.

As part of a panel with "Iron Fist" star Finn Jones, the head of Marvel Television Jeph Loeb brought the house down by calling to the stage Mike Colter, who plays "Luke Cage," Kristen Ritter, who plays "Jessica Jones," and Charlie Cox, best known for playing "Daredevil." Together, the quartet of Marvel's "street-level" heroes make up the superhero supergroup that will have their own 2017 show on Netflix. "Iron Fist" will be ready to stream in March.

The cast also introduced Weaver -- to thunderous applause -- as "The Defenders" antagonist, thought the role is still a secret.

Marvel is owned by Disney, the parent company of ABC News.

"Power Rangers"

The movie reboot of the hit 1990's TV show launched a trailer of its own Saturday at Madison Square Garden, an off-site for this year's Comic Con.

The movie, out on March 24, stars the likes of Bryan Cranston and Elizabeth Banks. The trailer immediately went viral, earning more than 12 million hits on YouTube alone.

"The Walking Dead"

Last season, we met new villain Negan, and the finale teased him taking out one of Rick Grimes' faithful followers.

"The Walking Dead" panel delved deeper into the new bad guy and showed fans a special bloody preview of season 7.

The preview clip was also tweeted out by the show after Saturday's panel and it's chilling. It's 3 minutes, 30 seconds long, giving fans a look into Grimes and how he's holding up after losing a dear friend. We still don't know who.

"Not today. Not tomorrow. But I'm going to kill you," Grimes tells Negan in the clip. He sits there shocked, blood on his face.

"The Walking Dead" is back on AMC on Oct. 23.

"Stranger Things" and "Westworld" Talk Season 2

Two new shows -- Netflix's "Stranger Things" and HBO's "Westworld" also enticed fans with panels.

For the Anthony Hopkins-led "Westworld," showrunner Jonathan Nolan said they are already working on a potential season 2 for the series that just debuted over a week ago on Oct. 2, according to Entertainment Weekly.

The retro-hit "Stranger Things" welcomed stars Millie Bobby Brown and David Harbour to talk about an "insane" season 2.

Fans weren't happy to hear from Harbour that "I can assure you that Barb is very much dead," according to Vanity Fair.

The Cosplay

You can't talk about New York Comic Con without mentioning the fans who spent hours, days, and even months creating costumes.

On Thursday, Tim Thomas of Brooklyn, N.Y., wore his 7-foot Incredible Hulk costume that he spent four moths making.

But the fun didn't stop there. Here are some more looks from the weekend.