Nameless King Swordspear (5e Equipment)
From D&D Wiki
This weapon may deal slashing damage or piercing damage (wielder's choice) and weighs 25 lbs.
While attuned to the nameless king swordspear, you gain a +2 bonus to attack and damage rolls. You deal double damage on any charge attack and you deal x3 damage on critical hits, rather than x2.
The nameless king swordspear holds six charges that can be expended to cast certain spells through the weapon. Using an action, you can use two charges to cast lightning bolt as a 4th level spell, or you can expend four charges to cast chain lightning as a 7th level spell. After using this feature, all successful attacks made with this weapon during the next round deal an additional 2d10 lightning damage. All charges are regained at dawn.