Starbreaker (5e Equipment)
From D&D Wiki
Weapon (morningstar), rare (requires attunement)
Made by the first archmage of the Arcadian Mage Guild, the Starbreaker is a curious item. Built by an expert craftsman, the silver and gold body is incredibly light, with intricate markings layering the head's centerpiece, a large, opaque, deep blue gemstone.
When swung, the Starbreaker immediately absorbs all light in the area and condenses it, causing it's blows to explode with flashes of energy, followed up by a stark darkness. You have a +1 bonus to your attack rolls with this magic weapon.
Light Absorption. While you are in dim light, a hit with this weapon deals 1d8 extra radiant damage to any target it hits. In bright light, this damage increases to 1d10.
Darkness. When you hit a target with an attack that deals extra damage with Light Absorption, for a period of time this weapon absorbs all light around it. This weapon creates a 30 foot radius of darkness surrounding it until the start of your next turn, and every light source in the area, mundane or magical(so long as the source was casted at 5th level or lower) is immediately snuffed out or dispelled.