Transformation has never *not* worked for me. Though I haven't tried it on much of anything that I'd care to lose if it did.

You seem to get a good variety of creatures, with flying ones being fairly common. Seems a decent spell; but just kind of a "Oh there it is" type of spell. Maybe if you could pick what you wanted to change into (thus you could form a strategy around it) it would be more of a "I finally got Transforatmion" instead of "Hmm, wonder what this does" type of spell.