This unnamed changeling briefly pretended to be Katie Keel.
When a Mother Changeling arrived in Cicero, Indiana, she began kidnapping the local children and replacing them with her own children. This changeling took on Katie Keel's form and ordered the girl's father, Richard Keel, to take her back to her mother's house, as it was the changeling's nature to feed from the mother.
Richard was disgruntled and the mother, Dana Keel, was confused, since the real Katie loved spending time with Richard. The changeling accused Richard of being mean and having monsters at his house. To ensure he did not get in the way of her being with Katie's mother, the changeling killed Richard.
The next day, Dana took the changeling to Ben Braeden's house to celebrate his 8th birthday. To Dana's concern, "Katie" just stood there and watched the other kids have fun. When she tried to tell Ben's mother that her child might not be hers, Ben's mother Lisa told her the grief of losing her ex-husband was making her think things. Annoyed, Dana ordered "Katie" to return home with her.
When Dana woke up from a nap, she found her daughter staring at her up close. "Katie" asked to play before adding that she was hungry. Having been feeding off of Dana while she was asleep, the changeling left Dana with a painful mark on her neck, which Dana went to check in the bathroom mirror. "Katie" followed her and angrily banged on the door, demanding to be with Dana.
Once Dana came out, the changeling asked to go for ice cream. The disturbed Dana instead drove them to a nearby lake and sent the car straight into it with Katie locked inside. By the time Dana reached home, "Katie" was there, soaked and still asking for ice cream.
By night, the changeling began feeding off of a sleeping Dana. After Dana woke up, she decided to lock herself up in the bathroom as the fake Katie pounded on the door, screaming for her to come out. Around that time, Sam and Dean Winchester had discovered the Mother Changeling's location and killed her, causing this changeling and all of her siblings to die as well.