Going to be spending some time in Dragon Magazine #99's Treasure Trove II. The first item was originally written by Michael Persinger.
Ring of Energy
Uncommon wondrous item
This magical ring always has a gem of some sort in its setting. Upon command, a pencil-thin beam of energy can be made to shoot out from the gem toward a target. The beam has a range of 60 feet. The target can avoid the beam with a DC 15 Dexterity saving throw. If the save is made, the beam will continue along its straight-line path and may hit an unintended target that lies within range.
The power beam of the ring of energy loses potency as it travels outward. Against a target within 20 feet of the ring wearer, the beam does 4d6 points of damage; at 21 to 30 feet, it does 3d6 points of damage; at 31 to 40, 2d6 points; and at 41 to 60 feet, 1d6 points.
The beam only affects living things; constructs and undead are not hurt by it, but it will hit such a creature and in so doing expend its energy.
The ring of energy has four charges, each beam expending one charge. The ring regains 1d3 expended charges each day at dawn. However, if you expend the ring’s last charge, roll a d20. On a 1, the ring crumbles into ashes and is destroyed.