Fluttershy Thestral? · 1:45am Dec 29th, 2013
Interesting idea. Since FiM's debut we've gradually seen the introduction of additional pony species.
Gradually, it looks like we might end up adding them all to the group:
Unicorn became Alicorn. Pegasus becomes Thestral (or whatever everyone agrees to call Bat-ponies). All we need now is for Pinkie Pie to become a crystal pony and the Mane 6's species exemplar is in balance again.