Innistrad has Morbid. Given that it's a graveyard-oriented set, it makes sense to have a lot of goes-to-the-graveyard triggers. LibraryPlane is a library-oriented set (in theory, at least), so it makes sense that it have a lot of library-oriented triggers. So here's the debut of 'whenever you draw a card, do X' (debut in this set that is, although it's interesting to note that this particular trigger is somewhat rare. Looking up 'whenever you draw a card' on gatherer only yielded Hoofprints of the stag, jace's erasure, lorescale coatl, moonring mirror, niv-mizzet, the firemind and psychosis crawler). I didn't think an ability word was necessary though.

Now is this the right card for the trigger? Probably not, since you'll generally be attacking with it anyway. This is just a Blue way to say '~ can't block flyers (except in certain circumstances)'. Welkin Tern and co. seem to want to remind players that they should be used offensively, and this card accomplishes the same thing, albeit in a roundabout way. Also, there are cards that deny draws, like Sophistry at common, so the restriction may be relevant here and there.

This was an attempt at a very narrow top-down design. In thinking on Blue for LibraryPlane, I constantly had this picture in my mind of little imps flying books to the tops of bookshelves. So here's that card; it only bothers to fly when it has a book to return to its place. Hopefully I can convey this flavour via the picture.

Funny. This is the exact same mechanic I recently submitted for our community set design, right down to only gaining flying when a card is drawn on Flying Bears (See my comment at the bottom.)

Cool! Such synchronicity! Weird that we both hit on flying, since it's a little awkward with this trigger. That said, in a set with a lot of flying (like the community set) being able to block flyers is more relevant. Really I only chose flying to fill out Blue's quota for common flyers.

It seems like Shroud would be a better keyword for this trigger since it's a keyword that does most of its work on your opponent's turn. That way you really want to manage to draw a card on your opponent's turn, especially in response to his or her shock. Maybe I'll do that for a Green common.