Question: who plays abby in how i met your mother
Answer: Kristen Joy Schaal ( / ʃɑːl / ; born January 24 , 1978 ) is an American actress , voice artist , comedian and writer best known for current roles as Louise Belcher in Bob 's Burgers ( since 2011 ) and Carol in The Last Man on Earth ( since 2015 ) , as well as for playing Mel in Flight of the Conchords , the over-sexed nurse Hurshe Heartshe on The Heart , She Holler and Mabel Pines in Gravity Falls .