The Hellfire Shotgun is a small shotgun that fires bursts of Hellfire.
During the period when carnival stunt cyclist Johnny Blaze was separated from the Spirit of Vengeance known as the Ghost Rider, he attempted to kill the new Ghost Rider, believing him to be Zarathos. When Ghost Rider made contact with the shotgun Blaze was carrying, it absorbed some of his power and became a weapon capable of shooting hellfire and conjuring flaming motorcycles.
When the Mother of Demons, Lilith, manifested on Earth, the Hellfire Gun proved vital in its ability to destroy Lilith's demonic offspring, the Lilin. One of the Lilin, Creed threatened Johnny's family, so Blaze destroyed him with repeated blasts from the weapon. Creed was actually grateful for the assault and told Johnny that he finally brought him a measure of peace.
Blaze eventually learned the power of the shotgun came from within him and wasn't inherent to the weapon.
* Unlimited Ammunition: Unlike conventional sidearms, the Hellfire Gun never runs out of ammunition and can be fired repeatedly for an indeterminate amount of time.
Alternate Reality Versions
Ghost Rider (film) Universe (Earth-121347)
Johnny Blaze used a sawed-off Winchester 1887 lever action shotgun in his battle with Blackheart at the desert. It was given to him by Carter Slade. While initially doing little more than slowing Blackheart as he regenerated quickly, when transformed with the power of the Ghost Rider, it hit with enough force to liquidize the Demon, though at that point he could still regenerate thanks to the power he had consumed.