Watch Pantera Rehearse, Perform With Slayer's Kerry King in 1989 | Revolver

Watch Pantera Rehearse, Perform With Slayer's Kerry King in 1989

Texas groove-metal upstarts play "Raining Blood," goof off with thrash guitarist

Slayer's co-founding axeman Kerry King is widely cited as one of the forefathers of thrash metal — but did you know that he had a hand in shaping the biggest groove-metal band of all time, as well? Following a fateful first encounter with the band through a mutual friend — main man Anselmo's boxing coach — at a Dallas concert in 1988, the guitarist began chatting and jamming with the Cowboys From Hell on the regular, and even played a show with them the following year, on May 19th at Joe's Garage in Fort Worth, Texas. More significantly, King's otherworldly mastery of the musical dark arts was instrumental in spurring Pantera's evolution from a glammy heavy-metal outfit to a bonafide, southern-fried wrecking crew.

"Dimebag [Darrell] and Kerry sitting down with each other opened up Dimebag's eyes, and eventually the rest of the guys' eyes, to the power of thrash," Anselmo later recalled to Talking Metal. "The magic of it really influenced us to push our own music over the edge."

King never officially joined the ranks of Pantera — but reading between the lines of Anselmo's comments from the same interview, it appears that the topic came up least once. "He loved it, and it was a nice departure for him to jam with us, but ... I could say more, but I won't," the frontman said slyly. We may never know the full story, but thanks to the magic of YouTube, we can catch a glimpse — a grainy, long, loud, two-hour-long glimpse, natch — of what could've been. Watch King, Anselmo and Dimebag, et al., rehearse and perform a raucous mixture of choice Pantera and Slayer cuts below.