Blood Blade

You create a blade out of your own blood to use as a weapon.

You lose hit points equal to 1d6 plus your spellcasting ability modifier, and create your choice of a dagger, rapier, shortsword, or longsword that is made up of your own blood in your free hand.  Proficiency with the selected weapon allows you to add your proficiency bonus to the attack roll.  The weapon is magical, and you can use your spellcasting ability for the attack and damage rolls.  The spell ends if you let go of the weapon.  When the spell ends, the weapon dissolves into a puddle of blood.