Carbon Threads

You conjure thin, blade-like carbon threads around a creature within range. That creature must make a Wisdom saving throw to detect the threads forming and get out of the way; on a failure, it is trapped inside a cage of carbon blades and takes 4d6 slashing damage. While trapped, that creature is restrained, and each turn, it may make a Dexterity or Strength check against your spell save DC. On a success, it escapes and takes 2d6 slashing damage. On a failure, it takes 6d6 slashing damage. In addition, a creature may attempt to move out of the cage without making the check, but it takes 10d6 slashing damage if it does so.