Crimson Thorns

5th-level necromancy (hemomancy)
Casting Time: 1 action
Range: 60 feet
Components: V, S, M (the blood of the spell's target)
Duration: Concentration, up to 1 minute

You manipulate the ichor inside a creature with blood you can see within range. The target's blood erupts from inside it, forming sanguine spikes in a 10-foot radius arount it. When the spikes appear, all creatures within the affected area must make a Dexterity saving throw. The spell's target has disadvantage on the first saving throw it makes to resist the spell's effects. On a failed save, a creature takes 5d12 piercing damage and becomes restrained. On a successful save, a creature takes half as much damage and is not restrained.
A creature restrained by the spikes can use its action to make a Strength check against your spell save DC. If it succeeds, it takes 2d12 piercing damage and is no longer restrained.
Amplify 3. The affected area becomes difficult terrain for the spell's duration. When a creature moves into or within the affected area, it takes 2d12 piercing damage for every 5 feet it travels.