Olivia (Shapeshifter)

Olivia was the shapeshifter daughter of Bunny LaCroix who was spared at birth by Bobby Singer.

Early Life
Bunny LaCroix had an affair with a shapeshifter and got pregnant with Olivia. Though Bunny passed Olivia off as her husband Lance's, Olivia's real father came for her after she was born. He killed Lance when he tried to stop him but before the shapeshifter could take Olivia, Bobby Singer killed him. At Bunny's pleading, Bobby agreed to spare Olivia on the condition that Bunny lock her up for everyone's safety. Bunny pretended she lost Olivia and locked her in the attic of her house, however, she remained devoted to Olivia and Olivia to her, only letting her butler Phillip know the truth.

Season 10
After Bunny dies, Phillip takes pity on Olivia and releases her from the attic, giving her a job as a maid in the house as her cover. However, when Collette tries to steal a pearl necklace, Olivia takes on the form of her mother and kills Colette by pushing her down the stairs, though she later claims it was an accident as she was just trying to scare her. Phillip covers up Colette's death by locking her body in the attic and claiming she went off to clown college. When Bunny's family arrives for her funeral and will reading, Olivia decides to kill them all as she is disgusted with them for their greed and disrespect for Bunny. She is even more pleased when Sam and Dean arrive as it gives her a chance to gain revenge on Bobby. Taking on the form of Lance, Olivia decapitates Stanton with an axe. As a result, Phillip locks her back in the attic until an investigating Dean finds and releases her. In revenge for being locked back up, Olivia murders Phillip and takes on his form and lies to Dean about why "he" hid Colette's body. However, Sam discovers the real Phillip and texts Dean. Realizing she's been found out, Olivia tosses Dean into a wall and flees, quickly returning to her own form. After finding Sam and Dean with Phillip, Olivia pretends to be scared and then helps them get what they believe to be silver butter knives, but are really stainless steel. As a result, she passes the silver test and Sam and Dean stop suspecting her. While Sam and Dean are trying to figure out which of the family is the shapeshifter, Olivia drowns Detective Howard in the toilet and confronts her family with his gun, explaining herself to them. Before she can murder anyone else, Sam and Dean break free by shooting out the lock of the room they are locked in and Olivia and Sam engage in a game of cat and mouse, both trying to kill each other. Olivia explains Bobby's role in things and then realizes that Sam hasn't fired at her as he has no silver bullets. Before she can do anything though, she's shot through the heart by Dean from behind, killing her. Dean then fired several more rounds into her body, possibly as a result of the Mark of Cain.

Powers and Abilities

 * Shapeshifting - As a shapeshifter, Olivia had the ability to change her shape into anyone living or dead, leaving behind shed skin each time.
 * Superhuman strength - Disguised as Philip, Olivia was easily able to throw Dean across the room. She also drowned a grown man in a toilet.
 * Superhuman speed - Olivia was able to flee from the room where she had confronted Dean in and change shape before he could catch her.
 * Superhuman agility - As a shapeshifter, Olivia possessed quicker reflexes than a normal human.
 * Regeneration - As they can change their form easily, shapeshifters can heal non-fatal wounds, and even replace body parts.

Weaknesses

 * Silver - As a shapeshifter, Olivia is vulnerable to silver. Dean kills her with a silver bullet.