How to make someone mad???

mmk well there's this girl at my school and she is really really really mean. Today she called me ugly and fat. I'm mad and I really want to get back at her. Please only positive comments, if ur not gonna help, dont answer! she is rele stupid and dresses like an oversized 3 yr old. Plus she likes this guy who likes my bff so now mah bff is flirting with him.