System-announced group event that forms when enough mantaurs berserk together to heavy metal.
When Carl rolls two Alarm Trap Balls playing Megadeth's "Holy Wars... The Punishment Due" into the Club Vanquisher guild corridor, the Mantaur Guards all around start glowing with berserk status and the system flashes a warning that a Mantaur Mosh Pit is about to form. Carl doesn't know exactly what that means and doesn't want to find out.
The warning matches what Tipid told him about this season's mantaurs having a group berserking mechanic triggered by a certain kind of music, which is why the fourth-floor mantaurs walked around carrying blasting boomboxes. Azin's article on group berserking covers the details. In practice the corridor empties: the ogre runs, three berserking mantaurs chase him, and the rest charge Carl's group.
Mantaurs glowing with berserk status, screaming and swinging blindly at anything nearby, including each other.
The escalation state Carl deliberately triggers to clear his escape route.