Broom of Chastisement

Weapon (greatsword), very rare (requires attunement by a warlock)

This broom has a thick handle that appears worn smooth with use, and the bristles on the end are gnarled and covered in burrs. In addition to function as a +2 greatclub, whenever you successfully hit a creature with this broom, that creature must succeed on a Wisdom saving throw with a DC equal to 8 + your Charisma modifier + your proficiency bonus or you gain advantage on attack rolls against the creature for 1 minute. If you hit the creature again within this time, it must succeed the same Wisdom saving throw or suffer disadvantage on attacks you for 1 minute.

If you hit the creature again while you still have advantage on attack rolls against it, it must succeed the same Wisdom saving throw or you gain advantage on any spells or abilities it uses for 1 minute.