From a show called Martin Mystery (I think?). It's an evil transformation into "witches" and by that they seem to mean the Wizard of Oz style witch (no offense meant to any wiccan). May not be as pretty as some of the other "transformations" posted here so far, but I have to admit I'm partial to the idea. I also love the attitude and cackling/voice changes.
All in all, I find it pretty hot
But I'm a weird fellow.