Blood Magic - Blood Shards

You create two shards of crystallised blood and bind them to a blade or ammunition. You or someone else can make a ranged attack with a weapon or a melee attack with a weapon. If someone else attacks with the crystallised weapon, that attacker adds your spellcasting ability modifier, not the attacker’s, to the attack roll. On a hit, the target takes slashing damage equal to their weapon dice (1D4, 1D6, 1D8, 1D10 or 1D12 depending on the equipped weapon or ammunition) and 1d6 + your spellcasting ability modifier. Hit or miss, the spell then ends on the stone.

If you cast this spell again, the spell ends early on any crystals still existing.