DVD cover for Season 3 of Supernatural
Julie Garrison was an unseen villainess mentioned in "Bedtime Stories," episode 3.05 of Supernatural (airdate November 1, 2007). She was the second wife of Dr. Garrison and the stepmother to his daughter, Callie (the episode's tragic main antagonist).
Julie married Dr. Garrison following the death of his first wife (Callie's mother). At some point before the events of the episode, Julie turned heel and began poisoning Callie, who was eight at the time, with bleach, which led to Callie being hospitalized and placed in a coma. No motive was ever revealed for Julie's sudden heel turn, though it suggests Munchausen by Proxy. The episode saw Callie's childlike spirit committing murders in the style of fairy tales, which were read to her by her father, while Callie would spend years in a coma and grew into a teenager.
It was during her rampage that Callie left behind an apple, as a poisoned apple was the Wicked Queen's weapon of choice for Snow White. The apple revealed that Julie poisoned Callie when she was a child, and when Sam and Dean Winchester informed Dr. Garrison about this, he was shocked, as he was unaware of his wife's actions. However, Callie's spirit confirmed the fact when she appeared to her father. Regarding Julie, she passed away before the episode's events, and the episode ended with Callie deceased as well, after her father lets her go.