Devastating Blast

When casting a spell, you have an innate ability to anticipate your foes' as they attempt to evade you, and through expert placement, thematic expressions, or other means have learned to use their own instincts against them to devastating effect. You gain the following benefits:

• Choose one Spellcasting Ability for a spell you can cast. Increase the corresponding Ability score by 1, to a maximum of 20.
• Before you make an attack with a spell attack, you can choose to take a negative penalty equal to your proficiency bonus modifier. If the attack hits, you add double your proficiency modifier to the attack's damage. 
• When you cast a spell that allows a creature or creatures, to roll a saving throw to avoid some or all of its effects; when determining whether or not a creature(s) makes a successful save and the roll is a natural 1 on the d20  but before it suffers those spell's effects:
  • If part of a spell's effect is to deal damage you may treat that portion in a similar fashion as if you had rolled a natural 20 on the die roll using a spell attack against that target rather than if the creature had rolled a natural 1 on the die against your spell save. Treat the damage dice as the attack's damage dice ignoring any modifiers that are not also dice. Roll the "spell attack's" damage dice once and apply it as extra damage to every creature who rolled a natural 1 on the save. You are considered to have scored a critical hit against each of those targets. Creatures not subject to critical hits are immune to this damage.
  • You then resolve the spell as normal for all creatures, dealing the spell's damage (dice and any other listed modifiers as normal this time) in whole or in part and applying the spell's other effects.