A mission-specific boss during a branch of chapter 2.
It looks like a mini Darreus and when he spawns, every player's screen goes pitch black unless you have higher settings. Turning hitpoint bars on is almost a must if your settings are low.
It has a pull ability that targets only player-controlled MOS's. It's usually only interested in harrasing and not pursuing; therefore, barricades are a good tactic to lure it out and kill it quickly.