Bosses are strong enemies found at the end of every floor in The Gungeon. Defeating a boss allows the player to advance to the next floor.
Upon being killed, bosses drop a weapon or item of random quality, several Hegemony Credits, and one to three pickups such as hearts, ammo, or keys. Bosses will always drop a gun if the player has not yet picked up a gun on the current floor. If a boss from one of the five main floors is defeated without getting hit, they will drop a Master Round as well. Clearing a boss without getting hit will also cause it to drop doubled Hegemony Credits.
Every boss has a DPS (damage per second) cap as a way of stopping players from dealing high amounts of damage over a short time, so guns with high fire rate or high damage can't destroy bosses in seconds.