The Firemace is a weapon from Heretic. Although it looks like a regular mace, it is used as a ranged weapon. When fired, its spikes rotate and it launches Mace Spheres that bounce and break into a trio of smaller spheres. Using a Tome of Power allows the Firemace to launch huge steel balls that bounce around, seek enemies, and kill any non-boss in one hit. The power mode shots may also travel through teleports. Neither mode is capable of hitting ghosts.
A notable feature of the Firemace is that when multiple Firemaces are placed in a level, only one appears, while the rest are replaced by monsters. This allows for some minor randomization in Heretic maps.