Fallen Cavalcade is a boss that was added with the release of the game.
Fallen Cavalcade has a gray circle base with a Cavalcade barrel in front, and drone spawner in the back.
Fallen Cavalcade is similar to normal Cavalcade but far stronger. It moves with low speed and shooting powerful, high health and penetration bullets which can easily kill most players. These bullets have relatively low speed.
Fallen Cavalcade also constantly deploys weak drones, they have low speed, medium health, and lock on the closest player. Each drone deals approximately 12% of the level 60 glass-build tank.
Spawns by a randomizer.
The main ammunition of Fallen Cavalcade, bullets, have low speed and long reload, so your mobility and bullet speed is key. You can trick Fallen Cavalcade in missing by moving in a left-right pattern, and it will most likely miss a bullet. Bullets and minions can deal with this boss effectively, and if skilled enough, drones can also kill it fast. As a drone user, try to leave multiple drones near you while charging all others into Fallen Cavalcade after it shot the bullet.
Drones of Fallen Cavalcade may be a problem, but they deal with low damage. Bullet tanks do not even have to think about drones, because you can just spread your bullets and minimize the damage to drones. It is trickier to do with minions but still easy - you have to keep all minions between you and Fallen Cavalcade. If skilled enough, even a drone tank can keep multiple drones between Fallen Cavalcade and still deal damage.
Fighting in groups will demolish Fallen Cavalcade even faster: it will focus drones on one player and bullets on another. While it will do low damage to both players, it will take heavy crossfire and a lot of damage, and thus will fall very fast.