Claws of Ursine Fury

These clawed gauntlets were fashioned from the remains of a mighty bear, whose essence empowers you while you're raging. Their claws turn your unarmed strikes with your hands into magic weapons that deal slashing damage with a damage die of 1d8 (unless your unarmed strike damage is already higher). You must be raging to gain this benefit. When you take the Attack action and make one or more unarmed strikes with the claws, you can make one additional unarmed strike with them as a bonus action.

When you roll a 20 on an attack roll made with the claws, the target must succeed on a DC 15 Constitution saving throw or be knocked prone and maimed. A maimed target takes 1d6 necrotic damage at the start of each of its turns for 1 minute. This damage ignores resistance and immunity. The effect ends early if the target receives magical healing or if a creature within reach of the target uses its action to make a successful DC 15 Wisdom (Medicine) check. A creature can't be maimed more than once at a time, and a construct or undead creature can't be maimed.