Cage of Blood

You cause the blood within a creature’s body to rip free, forming a gruesome, crimson prison. Choose a creature within range that has blood. The target must make a Constitution saving throw. On a failure, their own blood erupts outward, shaping into a 5-foot-radius, 10-foot-high cage (cube) around them, restraining them for the duration.

• The cage is made of hardened blood, considered magical and opaque, blocking movement and line of sight.
• A restrained creature takes 3d8 necrotic damage at the start of each of its turns as the blood prison tightens.
• A creature can use its action to make a Strength or Constitution saving throw against your spell save DC, ending the effect on a success.
• If the creature dies while inside the cage, it violently bursts, dealing 4d8 necrotic damage to all creatures within 10 feet.

At Higher Levels: When cast using a spell slot of 5th level or higher, the cage’s radius increases by 5 feet, and the necrotic damage increases by 1d8 per slot level above 4th.