During the Hard Rock Festival in Germany, Opeth frontman Mikael Åkerfeldt took the time to explain to the crowd that he's still not in Bloodbath anymore, but tried to make it up to them with Napalm Death's progressive metal odyssey "You Suffer." I'm not sure when the band had time to learn the song, but they nailed it.
In fact, the festival let the band play over its set time so they could cover it twice!
