Shirley the Medium is a lime Chihuahua who has a frequently occurring role on the show as an anti-heroine.
She was voiced by Mary Testa.
- Heterochromia in her left eye.
- Large gold earring on her right ear.
- Wears a green dress with a purple cape and blue hood.
Shirley is a mystical fortuneteller whose primary pastime is casting curses on those who defy morality. She despises the greedy and the inhospitable, and subjects them to spells that only repair when their sins are reversed. Ironically, she is very fond of money; charging heavy fees on clients and selling herself on TV are some of the ways she obtains it. This is probably because she is poor (as shown in The Curse of Shirley).
- Refers to Eustace as "The Stupid One".
- Plays the saxophone.
Shirley's earliest known curse was brought upon famous pianist Velvet Vick, confining him within his own record in the episode Record Deal. The spell enabled him to escape only when the album was played, however she buried it deep inside a chest, removing that possibility.
Her services as a spiritualist are advertised on the Channeling Channel. It is in this way that she was found by a farmer seeking to communicate with his deceased brother. After warning him of the consequences of contacting.