Alyson Hannigan 1989, her first regular role on a TV series came when she was cast in the short-lived ABC sitcom "Free Spirit". As a teenager, Hannigan babysat for the children of her future "How I Met Your Mother" costar, Bob Saget. In 1997, Hannigan was cast to play Willow Rosenberg, Buffy Summers' best friend, on the television series "Buffy the Vampire Slayer". The show became a success, and Hannigan gained recognition, subsequently appearing in several films aimed at teenaged audiences, including "American Pie" (1999), "Boys and Girls" (2000), "American Pie 2" (2001), and "American Wedding" (2003). She also had a guest
Entropy (Buffy the Vampire Slayer) Entropy (Buffy the Vampire Slayer) "Entropy" is the 18th episode of season 6 of the television series "Buffy the Vampire Slayer". The Trio, riding ATVs, pursue two vampires through a cemetery; one of them throws a tree branch at Andrew, causing him to fall off and the others to crash. The vampires encounter Buffy and they fight. One vampire drops the mysterious disk that the Trio were after; Warren snatches it and the Trio escapes, unseen by the Slayer. As Buffy fights, Spike seizes one of the vampires and offers to stake him, provided that Buffy agrees to tell the