We can't talk about witches on television without mentioning about one of the most badass of them all: Willow Rosenberg (Alyson Hannigan). As much as this show focuses on Buffy (Sarah Michelle Gellar) pulverizing vampires to dust, it's also about Willow's struggle and mastery with witchcraft to help out her best friend — her dark magic especially becomes a crucial plot point in season six.