An idea I had last Saturday, when stream ended up talking about bats. Regular bats, and how they crawl/walk around on the ground, sneaking up to you to suck your blood. Or well, the vampire ones at least. What if there was a bat pony, who's regular wings wern't an addition but a replacement.
Also, I havn't really made that many batponies in the past. Only 1 or 2 throughout the years. So this is the closest it has gotten to that.