Dolmai's Chains of Force

Summoning powerful chains of crackling force energy, the caster makes a spell attack against a creature within sight. On a successful hit, the target is whipped and beaten by thunderous metal links of chain from the ether, taking 4d8 force damage. Then, the target makes a DEX saving throw against the casters spell DC, and on a failure is also restrained and knocked prone. Creatures of huge or larger size have advantage on the saving throw.