Since launching in 1975, Saturday Night Live has become a mainstay for comedy. And while the live TV sketch show is renowned for its timely and sometimes politically incorrect satire, it’s also been revered for its musical performances from rising stars and music legends. Granted, SNL’s music guest often lean towards more mainstream acts, but once in a while a hard rock (sometimes even metal) band will pop up on the show. So in honor of its 40th anniversary live special tonight (February 15), we’re counting down the top 10 heaviest musical guests to perform  in Studio 8H (along with some honorable mentions).