When System of A Down played Rock In Rio this weekend, they invited a pretty killer guest for the closing tune, Deftones' Chino Moreno, who joined the band for a fun rendition of "Toxicity." The clip above features the band's entire set from the weekend, so feel free to scrub back and watch the whole thing. Also, you can see full sets from Korn and Metallica.
Funny enough, the band later performed an impromptu set (although sans frontman Serj Tankian, it seems) at a bar for 80 people.
[via ThePRP]