The Flaming Mace is a flail weapon craftable in early pre-Hardmode. It has a 16.67*1/6 (16.67%) chance to inflict the On Fire!debuff. Stepping in water or submerging the head extinguishes it and the projectile effectively becomes that of a regular Mace.
Its best modifier is Godly or Demonic. Both modifiers increase the average damage output by the same amount.