Kylie Jennings is the girlfriend of Mike Hooks.
Sam and Dean Winchester discover a killer with a tattoo on his arm which reads "Kylie Forever". In order to identify the man, the brothers decide to track down every Kylie in the city, with Kylie Jennings being the last on the list.
Kylie expresses disbelief when the brothers tell her that her missing boyfriend had killed a complete stranger - Stan Hinkle. Although she does mention that Mike began acting weird once he put on the bunny mask, which the brothers found him wearing.
She informs them that she and Mike discovered it at a thrift shop. She admits to hating the bunny mask, having found it super creepy.