Debilitating Bolt

A spike of darkness shoots toward a creature of your choice within range. Make a ranged spell attack against the target creature. On a hit, the target creature takes 4d6 necrotic damage, and the next attack roll made by this target creature before the end of your next turn has disadvantage, thanks to the debilitating necrotic energy in the target creature until then.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each slot level above 1st.