Drone Cannon

The  is a weapon of alien origin which is added to Fallout 3 in the Mothership Zeta add-on.

Characteristics
It is the removed arm canon of a Guardian Drone. It fires a ball of energy that acts as a grenade, bouncing and then exploding after a period of about 3 seconds.

Obtaining
This gun can be found on the corpses of Security Drones, along with Alien Power Modules to power them. There is also a unique variant, named the Drone Cannon Ex-B, which can be recovered off the corpses of two experimental drones, both fully repaired and worth 1999 caps.

Appearances
The appears in the Mothership Zeta add-on for Fallout 3.