The ultimate villainous transition! Willow has gone dark a few times over the course of Buffy The Vampire Slayer, but the best was when the characters were shown the alternate timeline where Willow was actually a vampire! Willow is the ultimate in geek sheep, with her sweaters, overalls and mostly bland apparel. Her vampire alter ego on the other hand seems to be a fan of corsets in shades of red and black. I don't think we need to go too much into detail on what the difference in costuming represents.