Converge was so out of place on the Mastoklok tour because the last place a godly hardcore/grindcore/metalcore/noisecore band wants to win over new fans is opening for an adult swim band and Mastodon. The genre's just clashed a lot. Also, Converge thrives on more intimate settings. Try looking up some live videos from one of their headlining tours. Shit hits the fan.
07/22 - Melt-Banana
07/26 - Forever Came Calling & Primitive Man
07/30 - Warped (?)
08/05 - Knockout Kid
08/07 - Fireworks (?)