Well, I hadn't. Till now!
And it looks super creepy and weird:
Yep, that's a bat on a treadmill 😄
Now, here comes the interesting part. After doing a bit of digging, the video comes from this scientific paper.
As it explains, bats have become so specialized for flight that they have pretty much lost the ability to manoeuvre on their feet, let alone run.
However, the common vampire bat (Desmodus rotundus) which often sneaks up on their prey on the ground, is an exception to the rule as they have evolved to use their forelimbs (instead of the hindlimbs) to run in a unique fashion.
From what we know, this is the only bat species to exhibit this trait and it evolved from a bat ancestor who had previously lost the ability to walk.
The absence of a running gait in all other bat species so far surveyed indicates that running may have been lost early in the evolution of bats, evolving afresh in the vampires at a later time.
Much like sea mammals that evolved from land mammals that evolved from an ancestor that originally lived in the sea!
Funny how evolution works over millions and millions of years, abandoning certain traits only to revisit them later on when the proper circumstances arise :)