Louise

Louise' is a maid at one of the motels Sam and Dean stay at while in Hoople, ND as they attempt to get the Alpha Vampire's blood for a weapon to kill the Leviathans.

History
At the motel, after Emily has left and warned the Alpha Vamp of the Winchesters, Louise comes into the room and see Bobby's ghost who is extremely angry, having seen Dick on the TV and trying but failing to open the safe where Dean has put his flask. Bobby suddenly realizes the combination is his birthday and asks Louise for help. When she runs away, he jumps into her body and, as he bleeds ectoplasm, says he only needs it for a little while. Bobby then opens the safe, grabs the flask, and heads on out to find Dick.

In the next episode, "Survival of the Fittest", Bobby, still in Louise's body, sees Dick on a TV on display in a store's window. He goes to a shop and purchases a machete, then attempts to steal a truck. When he touches an iron chain in the truck, his spirit is forced out of Louise’s body. She begs him to let her go, but Bobby spots a newspaper article about Dick, who's being called "Man of the Year". He becomes very angry again, and repossesses her. Later, while Sam and Dean check the cameras at SucroCorp for Dick, Sam sees Louise show up and he recalls seeing her at the motel in Hoople. He realizes it's Bobby and tries to stop him from being seen and going vengeful. Bobby slashes at Sam with the machete, and starts to choke him, but sees his reflection in a windshield and realizes what he’s doing. He then gets out of Louise’s body and disappears. Sam picks her up and the brothers take her to a hospital.