Overwhelming Magic, Variant (5e Feat)
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Variant Overwhelming Magic
Prerequisites: Spellcasting or Pact Magic feature, your spellcasting ability 18 or higher
Increase your spellcasting ability modifier by 1, to a maximum of 20.
If one or more targets of your spell fails their saving throw by 5 or more, they take extra damage equal to twice your spellcasting ability modifier which is the ability increased by this feat.