Cassie Howard, played by Sydney Sweeney, is a main character in the HBO series Euphoria, known for her journey from a sweet, popular girl to a deeply insecure and emotionally volatile young woman desperate for male validation, stemming from abandonment issues and a difficult home life. Her storyline, particularly in Season 2, involves a self-destructive pursuit of attention, including a secret, abusive relationship with Nate Jacobs, which leads to public breakdowns and online discussion.