The Null Cannon is a Fallen weapon enhanced with Hive technology that is wielded by certain Splicer Captains and can also be picked up and used by Guardians. It can drop from Null Captains in Sepiks Perfected and Wrath of the Machine.
Damage from the explosion does not affect the Guardian using the weapon.
The Null Cannon behaves almost identically to the Scorch and Shock Cannons, but its projectile can only charge up for one stage of power before detonating. The Null Cannon also has slightly different sound effects than the Scorch and Shock Cannons.