Blood Dagger

You draw some of your own lifeblood to create a pair of daggers.  You take 1d4 necrotic damage that cannot be dispelled when you cast this spell.  You are then armed with a pair of magical blood daggers.  You get a +1 to attack and damage rolls with these daggers, and when thrown, they return to your hands at the end of the turn.  They do 1d4 piercing damage, and on a critical hit, so an additional 1d4 necrotic damage, and you gain that many temporary hit points.

At 3rd level or higher, the attack and damage bonus is +2. At 5th level, it is +3.