Staff of Withering
Source: Dungeon Master's Guide
Staff, rare (requires attunement by a cleric, druid, or warlock)
The staff has 3 charges and regains 1d3 expended charges daily at dawn.
The staff can be wielded as a magic quarterstaff. On a hit, it deals damage as a normal quarterstaff, and you can expend 1 charge to deal an extra 2d10 necrotic damage to the target. In addition, the target must succeed on a DC 15 Constitution saving throw or have disadvantage for 1 hour on any ability check or saving throw that uses Strength or Constitution.