Shirley is one of the few characters of the show not directly inspired by an existing Looney Tunes character, but she bears more than a passing resemblance to Melissa Duck. Although she seems reasonably intelligent, she speaks with a thick Valley Girl accent and is obsessed with superficial New Age paraphernalia. Her name is derived from fellow New Age aficionado Shirley MacLaine, while the latter part of the name is an obvious pun. More often than not, characters refer to Shirley as "Shirley the Loon" rather than "Shirley McLoon." Shirley is often pursued romantically by Plucky Duck and Fowlmouth. When not meditating or fortune-telling, Shirley hangs out with her Acme Looniversity classmates Babs Bunny and Fifi Le Fume. In one episode, while attending a high school dance, a bowl of punch is dumped onto Shirley's head. The sight of the red punch on her hands causes her to temporarily go insane. She then proceeds to destroy the school's gym in a telekinetic fit, similar to Carrie, after being doused with pig's blood. Shirley is a keen ballerina who has to face prejudice when attending an upmarket ballet school otherwise attended exclusively by Perfecto Prep swans. Jealous at her superior dance skills, they mock her accent and try to sabotage her performance at their recital, but are soon thwarted by Shirley's nimble moves and a behind-the-scenes Babs, staging a sabotage of her own. Shirley did not have an end tag. Shirley is voiced by Saturday Night Live alumna Gail Matthius, whose SNL character Vicky the Valley Girl loosely inspired Shirley. In the Japanese dub, Shirley is voiced by Mika Kanai.