Looking through the PDF of Bestiary 2, I find myself remembering the days in the 1980s when I'd sit in the back of the mall bookstore and leaf through the various gaming tomes I couldn't possibly buy all of.
Crystal Dragons, Aeons, and several others in this book remind of that golden era, when DMs had such a wide variety of unusual (and often new-age-y) creatures at their disposals, they couldn't possibly ever use them all.
Sure, some of the creatures are a little odd, but on the other hand, the vast variety will lead to some adventurer groups with a far different list of encountered monsters than the norm.
I personally can't wait to spring the Dullahan (aka Headless Horseman) and Animate Dream on my party!