Who is Punchline?

Harley Quinn's days are over! Punchline is the Joker's new companion. It all started on a school field trip. Joker killed several hosts while the class was taking a trip to a news tv studio. Alexis, later Punchline, was forced to announce the Joker's news live on camera. After that she was obsessed with him. Her whole room was covered in posters and she even wore t-shirts featuring the Joker. One day, Alexis had a fight with one of her classmates and killed her with her homemade laughing gas. The Joker watched and was convinced by Punchline: This is his new partner!