Osteo-Blade

After an extensive undead ritual, you are able to turn your forearm into a bladed weapon:

• Increase your Constitution score by 1, to a maximum of 20.
• Your unarmed strikes deal 1d6 + your Strength or Dexterity modifier Slashing or Piercing damage, instead of the bludgeoning damage normal for an unarmed strike. This weapon also has the Light property.
• You can pull the blade into and out of your arm (no action required). When the blade is your arm, it is undetectable except by magical means.
• You don’t need to eat, drink, or breathe.