Initially, I had thought it could be an episode dealing with bat ponies, which, as they are still highly mysterious and unknown in official MLP canon and I was highly interested in learning more, would be a welcome episode for me. But no.
Instead, the episode proved to be about vampire fruit bats, being "vampires" only in regards to the apples that grow in Sweet Apple Acres, and thus harmless to anyone (unless you're a juicy apple growing on a tree). But I had liked the fruit bats too the last time we saw them, and welcomed an episode on that too...even if I figured the plot probably wasn't going to be all that special.
And it was somewhat predictable. Applejack takes offense to the vampire fruit bats and wants them gone NOW, but Fluttershy, of course, wants to be more kind to them for reasonable reasons that the others don't see (like the bats help spread seeds for new apple trees to grow), and eventually they have to learn via Fluttershy that the bats were not as "bad" as they were first spun to be. You pick up on this plot line pretty quick, within the first five or so minutes of the episode, so you have a pretty good idea how this is going to end up and that's about it.
Kudos to the episode, then, because it presents a plot twist that I, I have to admit, did not see coming.
Twilight, being the industrious princess and element of magic that she is, gets an idea. Instead of just driving out the vampire fruit bats without mercy (as Applejack suggests), why not just use a spell to make the bats no longer interested in the apples? Y'know, like what she tried with the parasprites way back in "Swarm of the Century?" Only this time, Twilight does her research and makes sure this is a plan that would actually work as desired, and not just cause more trouble. She finds it can be done...if they can get the bats full attention...requiring Fluttershy to use the ever infamous "stare" on them, which Fluttershy has problems with not just because she doesn't want to see the bats driven out at all, and doesn't want to abuse the "stare" so.
But she does it anyway, and the spell is conducted as planned, and seemingly with success.
Only...something went wrong.
And Fluttershy starts to become a bit..."batty."
Okay, so I couldn't resist that set up there.
And the episode presents it in such a way that when the "big reveal" takes place, you already know it's coming, so it wasn't like it was any big shock...but until they start building into it, I really didn't think they were going to try something like this and were going to take the episode in a whole different direction.
Maybe if I had watched a few of the previews I notice were bouncing around, that wouldn't have been the case, but I don't really believe in previews when it comes to MLP. Namely because whoEVER it is that manages those previews typically does a lousy job with them and ends up spoiling too much, but what can you do?
So yeah, did like the "Fluttershy goes vampire pony and develops a taste for apples, in addition to going a little feral and starts getting dynamic with her flying for a change with the added implication afterwards once the gang fixes it and restores her to normal that the changes might not be as all gone as we might hope" twist to this episode, enabling the episode to live up to my heightened expectations for it.
That said, looking back, the episode is rather average, at least for MLP. If we open up the comparison to, say, cartoons in general, then it's still above average, and that's great, but for the reputation MLP has sent for itself, this is actually kind of a run-of-the-mill episode for them, the sort of episode you'd actually expect them to do for the show...so much so that I'm actually a little embarrassed (just a little) that I really didn't see it coming. There wasn't really anything especially special about it or dynamic, writing was fair, but not stellar, and as already stated, a bit more predictable than preferred after certain clues were dropped in the episode that were more obvious than I would've liked.
But I'm a sucker for suspense, so I'm a little bias on that matter.
And nonetheless, it's a fun episode, and I enjoyed it, and that's what counts. Given the intended audience for MLP, this episode fits that slot nicely and I really wouldn't change that. The song wasn't too bad either, I suspect it'll be one of those songs that'll grow on me more over time.
Other than that, I don't really have anything else to say about the episode, so I guess we'll be quick about this one and end it here.