The Big Barrel has a purple body with a black handle, which has a black marking on it. It also has a crystal-like white object on the top, which is possibly its power source.
Big Barrels can be dropped from defeated Black Arms who wield them, or released from breakable Containers. Touching one will make the playable character pick it up automatically, and pressing // (whether on the ground or in mid-air) while using the crosshair to aim will fire it.
The Big Barrel has very low ammunition, like most other cannons, lasting for only eight rounds. It has a medium range of attack.