This gun was found hidden in the depths of the Forge. The design resembles a dragon's head with the gun's barrel as the dragon's tongue.
How it works:
It's almost like the Flame Hand. It shoots a fireball that leaves a trail of fire on the ground. The fireball can pierce enemies. The fireball doesn't go very far so you can't cover the entire room with a trail of flames.
If you're wondering, the quote is a reference to Skyrim. It's the dragon shout for Fire Breath. ;)