Akhenen's Threads of Fate

You attempt to attach up to three mystical threads to creatures you can see. These threads are invisible and do not affect the creatures in any way until you sever them. Creatures can make a Charisma saving throw to avoid having any threads placed on them. Whenever an affected creature makes an attack roll, ability check, or saving throw, you can choose to sever a thread as a reaction. Severing a thread allows you to add or subtract an amount equal to your Spellcasting ability modifier from the roll. 

At Higher Levels. When casting this spell with a spell slot of 6th level or higher, you can place one additional thread for every spell slot level above 5th.