Bone Plating

Nothing goes to waste when even the bones of the deceased can be used to further your ends!
After gathering enough bone matter, you spend 10 minutes concentrating, during this time the bones must remain within reach, after concentrating for ten minutes the bones slough together and form protective plates over your armor/clothing granting you 5 temporary hitpoints for every 5 lbs. used (max 20lbs). 

While the temporary hitpoints persist you have resistance to bludgeoning, piercing, and slashing damage from non-magical weapons.

When the temporary hitpoints expire, shards of bone are hurled out from you, dealing 1d6 piercing damage to creatures within 5 ft.