Baneful Vortex (Arteria)

Up to three creatures of your choice that you can see within range must each make a Charisma saving throw. Whenever a target that fails this save makes an attack roll or a saving throw before the spell ends, the target must subtract 1d4 from the attack roll or save.

Creatures that fail the saving throw can barely move as you generate minor singularities that alter their center mass. Until the end of your next turn, the creature's speed becomes 0 and it automatically fails Dexterity saving throws.

Using a Higher-Level Spell Slot. You can target one additional creature for each spell slot level above 1.