What we’re calling the Glee curse begins with the death of Cory Monteith. Monteith, who played Finn Hudson on the show, struggled with substance abuse issues for most of his life. While he was on Glee, he began a romantic relationship with Lea Michele and managed to get sober for a while.
Unfortunately, Cory died of a drug overdose in 2013. Glee was still airing at the time, and the show addressed the death of the character with a full episode dedicated to Finn and Cory.