If Sleep is his indica, then High on Fire is Matt Pikes sativa band. After establishing himself as a master of low and slow, the stoner-metal guitarist started the blistering High on Fire to make sludge that was faster, meaner and heavier, and their 2002 sophomore record is the obvious entry point. Whereas Mastodon had glimmers of prog grandiosity in their sound from the jump, Surrounded by Thieves is down-and-dirty sludge metal with burly riffs, thudding drums and Pikes goblin warrior croak. Horns up.