'Game of Thrones': Who's Chasing Arya in the Season 8 Trailer?

Game of Thrones is heading into the second week of the season, but some fans are still focused on one question from the trailer: who is chasing Arya?

Warning! Spoilers for Game of Thrones lie ahead!

The official trailer for Season 8 of HBO's Game of Thrones found Arya Stark (Maisie Williams) running in terror through a darkened stone corridor. As many fans have pointed out on forums and social media, Arya is not scared of much. The daughter of Ned Stark has hardly ever run from a challenge, and with the powers of a Faceless Man now at her disposal, it is daunting to imagine what might have her so scared.

[Spoilers] Someone is chasing Arya in the trailer! from r/gameofthrones

In addition, fans have noted that Arya already knows about the White Walkers and the Army of the Dead at this point. Thanks to Bran and, after the season premiere, Jon Snow, she knows everything there is to know about the frozen enemies, including the fact that her Valyrian steel dagger can kill them. Hopefully she will soon have an obsidian weapon from Gendry to defend herself as well.

Still, the trailer finds her running in terror, and fans are daunted by the question of what it could be. Many have pointed out a shadowy figure behind Arya, suggesting that she is being chased by either a human or a wight. On the Game of Thrones subreddit, fans have proposed many ideas for who it might be.

"I think it's Catelyn, raised by the night King from the crypts of Winterfell," wrote user jakej1097. "She wouldn't be that scared of any human. Sure, she may run from a human, but her face is sheer terror. Whatever she's running from, it has to be something waaaay worse than anything she's seen before!"

In the books that form the show's source material, Catelyn Stark is raised from the dead by Beric Dondarrion, and she wanders Westeros as "Lady Stoneheart," taking her vengeance on anyone who had a hand in the Red Wedding. The show could acknowledge that plot line by bringing a zombified Catelyn back now. Even if Arya could stop her, she might be so shocked by the sight that she would run, as in the trailer.

Another popular theory is that Cersei's reanimated bodyguard, The Mountain, is chasing her. In that case, even Arya's assassin skills would not help her in a one-on-one fight against the brute, who remains on her "list." This could also help in the redemption of Ser Gregor "The Hound" Clegane, if he arrived to rescue Arya. The show has teased a showdown between the Clegane brothers, and this could finally be it.

Either way, fans will know soon enough. Game of Thrones is in its shortened final season, with only five episodes left to go. The show airs on Sundays at 9 p.m. ET on HBO.