Millie as Harley Quinn is an engine in the DC Super Friends theme. It features Millie painted as Harley Quinn with comic book details and wearing a mask.
- Millie as Harley Quinn features "H. Quinn Millie" written underneath instead of "Millie". Thomas as Superman, Diesel 10 as The Joker, Spencer as Cyborg, and Diesel as Batman also feature this exception. However, her re-release has "Millie" under her chassis.