The Torturer's Chains

You summon fourth chains from your Patron's domain to wrap around the target who must succeed on a Dexterity Save equal to your Spell Save DC or be Restrained until it Succeeds on a Strength Saving throw equal to your Spell Save DC. This Spell is not able to kill the target, if the target would be reduced below 1 Health the Spell dissipates and releases the target.
The Chains appear however you see fit, perhaps they are black heated metal with spikes for a Fiendish Patron, or they appear as thick heavy vines if your Patron is the Archfey
The Spell deals an additional 1d6 of Damage with each level it is cast above 3rd.
The Spell Lasts for 1 Round when cast at Lv. 3, 2 Rounds when cast at Lv. 4, and 3 Rounds when cast at Lv. 5

When the target is hit by this Spell, roll 1d4 to determine the effect of the chains:
1, 2, or 3 - The Chains squeeze the target causing the to take 1d6 Damage of your choosing.
Fire
Cold
Lightning
 
4 - The Chains squeeze the target dealing 1d6 Necrotic Damage and heals the User for half the Damage done.