Asphyxiating Shell

You toss a piece of rubber at a creature within range. Make a ranged spell attack against the creature to encase it in a shell of asphyxiating rubber. On a hit, the target takes 1d8 necrotic damage, and it can’t regain hit points until the start of your next turn, encasing it in a layer of suffocating rubber. This spell’s damage increases by 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).