Blood thorns

You create a magically dagger which draws your blood and does damage that's a quarter of the enemy's last damage equal and half you unarmed strike max damage. You then drip blood on your weapon and point it at the target. Then spikes of blood centred on a point you choose emerge from the ground doing 1d10 + weapon damage for 30 feet. It also makes it rough terrain. At level 7 it does an extra 1d10+ weapon damage it also increases in this way at level 12 and level 17