Freak the fuck out and go to a hospital. When they find out it?s irreversible, I?ll get electrolysis to eliminate the troublesome hair from my body. Then I?d buy some new clothes and go to a furcon in an attempt to get laid. Even if that fails, I?ll at least try and make friends with a cute catgirl. If things get too hard for me, though, I?d just commit suicide (especially if I was a reptile; I?m hate having cold as a base state, not to mention I?m scared of snakes) or have someone euthanize me.
If I?m a dragon, I?d just go ?FUCK YEAH!?, start flying around breathing fire and shit, and eventually take over the world. If I?m a bat, I?d tell everyone I?m Batman.
But it really does depend on what species I am and how it will affect the world on a global scale. I?m not sure the human population, even with all its remarkable adaptability over the years, would be able to sustain itself for long when half of them are
part-animal. (And yes, I know, humans are technically animals too, but you know what I mean.) And it would take, like, over fifty years for people to finally get to a point where they can tolerate and/or not be scared shitless of all these ?otherkin? suddenly appearing.
However, at least a lot more people would be more open about having furry fetishes, if they?re furry themselves.
Going off on a bit of a tangent, this reminds me of this yaoi doujinshi I read where that guy?s cat dies, but then it?s resurrected from Heaven or something as a catboy (although I think it still had the mind of a cat, since it still acted much like one), and then the guy and the catboy start a relationship. At least, that?s the gist I got from the pictures (I can?t read Japanese).