If you want to go as something really simple but relevant this Halloween, consider Harley Quinn’s signature t-shirt from the Suicide Squad movie. Though the reviews were mixed, the costume should be a big hit this Halloween. It’s easy to simply buy this Daddy’s Lil Monster shirt and wear it with shorts and boots and hair in ponytails. That’s all you really need, forget the crazy accessories, tattoos, jacket, makeup, etc. This t-shirt from the movie that Margot Robbie is really all you need.