Clotting Chains

You contort your body in a bizarre pattern making your foe's blood run cold. Each creature you choose in a 15-foot cube originating from you must make a Constitution saving throw. On a failed save, a creature takes 2d6 necrotic damage, has it's movement speed reduced to by 10 feet, and cannot make opportunity attacks until the start of your next turn. On a successful save, the creature takes half as much damage and can also move and react freely.

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