A small Mandalorian season 3 moment could be setting up the Ahsoka spin-off

gamesradar.com:

A small moment in The Mandalorian season 3 episode 1 could be laying the groundwork for the Ahsoka show with a key connection to Rebels' Ezra Bridger. Warning, the following contains spoilers for The Mandalorian season 3 premiere and the Rebels finale! Turn back if you're not up to date! 

Early in the new Mandalorian episode, Din Djarin and Grogu are travelling through hyperspace together, and in all the blue, Baby Yoda notices a strange shape moving with them. As he looks on, the shape gets clearer, revealing a huge creature. Those who know their Rebels will recognize this as a purrgil, which are giant space whales that can travel through hyperspace. 

The purrgil have a major link to the Rebels finale. In a battle against Grand Admiral Thrawn's fleet, Ezra Bridger, who had developed a bond with the creatures earlier in the show, was able to defeat Thrawn with assistance from the space whales. A purrgil took Thrawn's ship in its tentacles and jumped to hyperspace, eliminating him from the battle – the catch is, Ezra was also on Thrawn's ship, and the two have been lost ever since. 

Thanks to Ahsoka Tano's episode of The Mandalorian season 2, we know that she's searching for Thrawn, and that presumably includes Ezra, too. Purrgils showing up in the latest episode is a reminder that the duo are still out there somewhere, as well as a live-action introduction to the creatures that could play a huge part in the Ahsoka spin-off show. 

Ahsoka has already found its live-action Ezra Bridger, too, with Eman Esfandi cast in the role. Thrawn, though, has yet to be cast, though it seems safe to assume he'll be showing up in the series. 

The Ahsoka show will arrive on Disney Plus sometime in 2023. While you wait, check out our guide