Greatsword of Cleaving (5e Equipment)

Weapon (greatsword), very rare

This burnished black greatsword excels at fighting against and destroying armored enemies. You have a +1 bonus to attack and damage rolls with this magic weapon. Once per turn, whenever you hit an armored creature (includes natural armor) with this weapon, you may make a DC 12 Strength check. On a success, the target's AC is reduced by 1 until they finish a short or long rest. A creature's AC can not be reduced by more than 2 with this effect.