Blade Maiden

You channel cursed energy into a weapon and scrap of metal which spring to life and start to build an iron maiden. The scrap of metal stretches out into an iron maiden while the blades settle within. A creature targeted by this spell has to make a dexterity saving throw against your spell save DC  or be trapped in the maiden. Creatures in the maiden are considered grappled and if they end their turn in the maiden they will 3d8 piercing damage and will continue to take 3d8 piercing at the end of their turn damage until they escape with a strength saving throw equal to or above your spell save DC.

The maiden has 30 hp and an AC equal to your spell save DC.