The Miniature Giant Space Hamster.
Now, being a HUGE Bioware fangirl, the first thing I thought of upon reading this was....
Commander Shepard's SPACE HAMSTER!
If you had Space Hamster as a pet in Mass Effect 2, you can find your hamster in Mass Effect 3 as well. Space Hamster is even in the Citadel DLC!
There is also a Space Hamster in Mass Effect: Andromeda.
So how could you NOT think of Bioware's Mass Effect when you think of Space Hamsters?
As it happens, this is PRECISELY WHAT YOU SHOULD THINK OF.
Back in the day, Bioware was the first studio to develop Baldur's Gate games. In both Baldur's Gate and Baldur's Gate II, a ranger named Minsc has a "Miniature Giant Space Hamster" named Boo in his pack.
If you watched the Citadel DLC video above, you heard Shepard tell his hamster to "Go for the eyes." This is what Minsc used to say to Boo.
Space Hamsters. From Baldur's Gate to Mass Effect to Baldur's Gate. The ouroboros Easter egg.
Thank you for coming to my TED talk. 😉