Weakening Curse

Casts a short-lived curse of weakness on a target creature, lowering the creature’s ability with physical attacks for the duration. The creature must succeed on a Strength or Dexterity saving throw (whichever is the main source of their attack skill) or become cursed, lowering a creature's bonus to attack skill and damage to -1. Affects creatures of CR rating 5 or lower normally. If cast on creatures higher than CR 5, it has advantage on the saving throw.

At higher levels, the effectiveness on stronger creatures increases. If cast at 3rd level, it affects creatures of a CR rating of 7 or lower normally, increasing by 2 CR for every spell level beyond 3rd. When cast at 6th level or higher, you can now target two creatures with one cast.