Wowhead have datamined the recent addition of the Sarge mount to World of Warcraft and have uploaded a video featuring the mount in their model viewer environment.
Blizzard's official preview of Sarge.
In the video you can see the different animations our rat friend has, though its eyes are unfortunately not moving in the preview which gives off a bit of a weird vibe. The mount special animation is Sarge jumping up into the air, doing a twirl, sniffing, and then landing. All this happens while being surrounded by Rare Hearthstone cards and a beautiful trail of blue particles.
Look at those Rare cards! Now do it for the other rarities.
Keep in mind that this is just an initial look at the free mount that will soon be available once Mercenaries comes out and may not be final, also, datamining is not always perfect so we'll have to wait and see in-game for a final look. Sarge will be available to World of Warcraft players in October 2021 when Mercenaries launches and will be obtainable for free by playing Mercenaries.
Speaking of Those Eyes
Wildchargeart on the /r/wow reddit created an edit of the mount to showcase more anatomically correct rat eyes, though it should be noted that there is still a bit tooo much color but it would be a welcome improvement to make.