Metallica in 1983 doing The Mechanics (from the legendary No Life 'til Leather tape) i.e. the original version of The Four Horsemen with Dave Mustaine on guitar. I'm sure you're all familiar with how Dave got booted out of band soon after and later recorded The Mechanics with his new band Megadeth.
It's awesome to see this old video tape!!! (and if you've never been into this you're just gonna think it's shit, haha).