A direwolf is a Stark's best friend, and the latest fan theory making the rounds suggests they're more than just adorable companions.
In the fan theories subreddit, GoT fan and animal symbolism enthusiast mybustersword dove into the stories of the Starks' and Targaryens' beloved fantastical pets, direwolves and dragons, and how they reflect on the fates and qualities of their owners.
Sansa's direwolf was named Lady, and Sansa became the lady of Winterfell.
Nymeria was named after a fierce female warrior, which we all know was Arya's destiny, too.
Not only was Ghost the "bastard" of the litter like Jon Snow, Jon Snow died and became a "ghost."
The name of Bran's direwolf, Summer, could mean that Bran dies when Winter comes, or saves the world from Winter. Alternatively, Summer sacrificing herself to save Bran could foreshadow her own demise.
Grey Wind was as loyal and obedient as Robb Stark himself. They were both killed at the Red Wedding, and had their heads sown on to other corpses as a brutal act of desecration.
Mybustersword also analyzed the names of Daenerys's dragons:
The dragons I think are similar. Named after her 3 male relationships Viserys for her brother (Vyserion) , Drogo her lover (Drogon), and Rhaegar (Rhaegon) for her other brother. Which dragon was killed? The brother who died. Drogon is her strongest and fiercest dragon. I don't believe he will die because he promised to conquer the lands for her, and he will. He will also be the one to kill Vyserion the ice dragon, as the man did to the brother.
Rhaegal was named after Rhaegar , and we do not know much about Rhaegar or Rhaegal at this time. It's known he was an artist and a fighter and a lover and took Lyanna stark as his new wife. Process of elimination One could say, that Jon will ride Rhaegal as that was Jon's father, and would represent Rhaegars love for both Stark and Targaryen.
TL;DR This theory suggests that Drogon will kill Ice Viserion like Drogon killed Viserys, and that Jon "Aegon Targaryen" Snow will ride Rhaegal to rep Rhaegar's love for both Starks and Targaryens.
Read the whole theory here.