Impurity Spear

The grayed unicorn horn that rests at the top of this sickly spear is fractured and slowly leaks a silver, corrupting fluid. An impurity spear is the rare version of a purity spear, a sad reminder that while unicorns are paragons of good, even their magic can become toxic when mistreated.
Corruption: This magic spear has 10 charges and regains 1d6 + 4 expended charges daily at dusk. You can expend 1 charge when you hit a creature with the spear to cause it to inject the target with its corrupting fluid. When you do, the target must succeed on a DC 15 Constitution saving throw or gain 1 point of corruption, which lasts for 1 minute. A creature takes 1d4 poison damage at the start of each of its turns for each point of corruption it has, up to a maximum of 3d4 poison damage. This poison damage ignores resistance and immunity.
A creature with at least 1 point of corruption can make another Constitution saving throw at the end of each of its turns. On a success, it removes 1 point of corruption. A creature is poisoned while it has 3 or more points of corruption. If you expend the spear's last charge, roll a d20. On a 1, the tip of the spear shatters, and the spear becomes a nonmagical quarterstaff.
Charge: If you move at least 20 feet straight toward a target and hit it with the spear on the same turn, the target takes an extra 1d8 piercing damage.

Item type

Weapon, Melee