Unstable Necrotic Orb

You conjure an orb made from what appears to be a small dark blood-like substance at a point you can see in range. Any creature within 10 feet of the orb takes 1d4 force damage as the orb rends blood from their body, increasing its size. The orb exists for three rounds as long as you maintain concentration on it. However, if at any point you drop concentration on it or the duration ends the orb explodes, forcing any creatures within 10 feet to make a dexterity saving throw. Upon failing the dexterity saving throw, each creature takes 3d6 necrotic damage.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 necrotic damage and 1d4 force damage for each slot level above 1st.