Annie/Dr. Gaines

Dr. Gaines was a surgeon who works at Sioux Falls General Hospital until his form is taken on by a Leviathan.

Hello, Cruel World
After the Leviathans have dispersed into the public water supply, one of them infects and possesses a little girl named Annie who was taking a drink from a fountain at a park. Annie meets with Edgar, who orders her to get the other Leviathans under control since the boss didn't want them to attract attention.

Annie goes to Sioux Falls General Hospital and met a surgeon named Dr. Gaines. After asking him if he was "Dr. Sexy", she assumes his form and then killed him. Gaines remains this Leviathan's primary identity from this point on.

Now as Dr. Gaines, he begins feeding on patients in the hospital. He is noticed by Jody Mills who escapes the hospital. Later Edgar comes by with the two swim team boys and Gaines shows them the hospital as well as providing them new hosts. Gaines later catches Bobby in the morgue investigating the body, and Bobby shoots him, but Gaines is unaffected. Bobby flees the morgue.

The Girl Next Door
At Sioux Falls general, Dr. Gaines and the Leviathan Head Nurse are preparing a patient for surgery - or "dessert" as they call it. The Leviathan impersonating Dr. Gaines receives a call alerting him to the Winchesters' arrival at the hospital, but he is too late to stop Bobby from driving away in a stolen ambulance with Dean and an unconscious Sam. Three weeks later, Bobby reports that the Leviathans at the hospital - Dr Gaines, the head nurse and an administrator - have disappeared.

How to Win Friends and Influence Monsters
Gaines begins experimenting on humans to make them more compliant. However, a small number of humans react badly to the Gaines' experiments and become ravenous, cannibalistic creatures which go on to commit a spree of murders. These killings caught the attention of the media. Dick Roman shuts down the project and makes Dr. Gaines "bib" himself as punishment for his carelessness. This punishment involves Gaines being forced to wear a lobster bib and then literally eating himself starting with his right arm. After the punishment is complete, nothing is left of Gaines except a black stain on the bib.

Appearances

 * Season 7
 * Meet The New Boss (inside Castiel)
 * Hello Cruel World (as Annie, then Gaines)
 * The Girl Next Door
 * How To Win Friends And Influence Monsters