The Violent Boyfriend was Prue Halliwell's ex-boyfriend who violently attacked her in a heat of rage in her teenage years. After the incident, he disappeared, causing the Piper to wonder if their Grams had anything to do with it.
When Prue accidentally wished that she wanted something that she could only get if she was seventeen, a genie granted her that wish and turned her back into her seventeen year old self. At the age of sixteen, Prue was going through a rough rebellious stage. When out one night with this boyfriend, he attacked her. Penny Halliwell went crazy after she found out and the boyfriend disappeared not long after that. The events of this would later be played out again when she gets tricked into going on a date with a warlock and he attempts to kill her.