Every 5 to 10 years there is a band whose arrival signals a sea change in the heavy metal landscape, be it Black Sabbath’s invention of the form, Iron Maiden’s punk/speed metal hybrid, Metallica’s time signature shifting thrash, or Pantera’s grungy southern sludge groove. Killswitch Engage is one of those bands. While their lowbrow nu metal contemporaries were unsuccessfully attempting to bastardize rap and doing it all for the nookie, Killswitch melded the aesthetics of hardcore to melodic, radio-friendly metal hooks to popularize a genre that would come to be known as metalcore.

There would be a million bands that would attempt to emulate Killswitch’s unique brand of beauty and ferocity. Most of them would only succeed in sounding like pale imitations. To this day the band stand as one of the most vital in the genre and their live shows continue to amaze.

From the band’s second album, Alive Or Just Breathing, the Massive Metal Monday track for this week is “Fixation On The Darkness.” Interestingly, the album features the vocals of original singer Jesse Leach who would leave the band before the video for the song was shot. This video features his replacement, Howard Jones, and was shot live to introduce the world to the new singer and his skills.

What happens when you stick one of the world’s biggest mainstream metal bands in a small club, down a guitar player (to a family emergency) and have them play for a bunch of aggro hardcore fans? Well, if it’s Killswitch Engage, they bring out the very heaviest of their material, invite the crowd to get go as crazy with the moshing and stage diving as they want to and proceed to win the whole place over with a set full of passion and brutality.

Watch Kilswitch Engage’s full This Is Hardcore set from Philadelphia’s legendary Electric Factory here below.