Mercedes Alicia McNab (born March 14, 1980 in Vancouver, British Columbia) is a Canadian actress whose most known performances include Harmony Kendall on Buffy the Vampire Slayer (1997–2001) and its spinoff Angel (2001–2004). She is also known for her role as pretentious Amanda Buckman in Addams Family Values (1993) and Misty in the horror films Hatchet (2007) and Hatchet 2 (2010).
An only child, McNab's father is former English soccer player Bob McNab.
McNab received her first notable acting role in 1991 when she appeared as a girl scout selling cookies in The Addams Family. She then received a more prominent role in the 1993 sequel Addams Family Values in which she portrayed a snobby camper named Amanda Buckman. McNab's next breakthrough came in 1997, when she was cast in a recurring role on the TV show Buffy the Vampire Slayer on The WB. McNab played Harmony Kendall, a vapid popular high school student who eventually becomes a vampire. She appeared in 16 episodes over four years. McNab reprised this role when she was cast in the spin-off Angel, which starred David Boreanaz. She became a series regular during the show's final season, airing from 2003-04. Since the cancellation of Angel, McNab has gone on to guest star in popular TV shows including Psych and Supernatural. In 2007, she appeared as a lead role in the horror-slasher movie Hatchet, directed by Adam Green. She later briefly appeared in the 2010 sequel Hatchet 2 and has since starred in a number of Direct-to-DVD horror movies such as Dark Reel and Thirst, as well as the TV movie Vipers alongside Tara Reid.