After Party Massacre (2011)

After Party Massacre (2011) 

Scarlett is a fan who enters a live performance by two heavy metal bands called Incantation and Soulless. While she has a physical altercation with her former boyfriend, she has flashbacks of her past. Then she turns into a bloodthirsty killing machine who kills her attacker, and sets out to kill anyone in the audience, or even the band members. (IMDB chribren)

Grindhead Jim Deabenderfer (R)