Wowtcg.com has previews of the loot coming in the next TCG expansion deck, Crown of the Heavens!
Being the common loot card, the Gregarious Grell is first up on the list. Their preview page has an image of both the physical card and a screenshot of what the pet will look like in game. There's no indication on the page that it will have any special or unique animation/interaction, though.
The Eye of the Legion (coming a couple TCG expansions after Crown) will match perfectly with this grell companion! Pet collectors won't have to be a warlock to feel like one now. :P If only we could have them both out at the same time.