Arcane Contradiction

All spells within six inches of the owner of this feat have their elements and/or effects altered. If a spell has an area effect that would pass through the range of the Arcane Contradiction, the spell's effects only change within the area of the Arcane Contradiction, and return to normal upon leaving the range. This includes touch/melee spells.

The Contradiction changes are as follows: Fire becomes Cold, and vice versa; Necrotic becomes Radiant, Radiant becomes Healing, and Healing becomes Necrotic; Thunder becomes Lightning and vice versa; Poison becomes Psychic and vice versa; Acid becomes Force and vice-versa; Buffs become Debuffs and vice versa (e.g. Hex would give advantage instead of disadvantage, Bane and Bless would swap effects, etc.); and any other inversions the Dungeon Master decides upon as they are potentially encountered. Magic items are unaffected, except for potions. The user's own spells are also affected by Arcane Contradiction.

Immunities, Resistances, and Vulnerabilities are not changed, no matter their source, and are calculated after all instances of Arcane Contradiction have been resolved (i.e., a creature immune to Necrotic damage hit with Inflict Wounds would treat the spell damage as Radiant, since the spell would no longer deal Necrotic damage).

At 10th level, you can use Distort Arcana once per short rest as a reaction:

You can temporarily pass on your Arcane Contradiction to a creature within range. It remains active as if you were concentrating on a spell, up to 1 minute, or until your concentration is broken or dropped. The Contradiction has all the same properties, no matter who it's on. The targeted creature makes a DC 18 INT Saving Throw to avoid receiving the Contradiction. A creature can choose to fail the save, if they would like to. This action cannot be countered by Counterspell or Dispel Magic and cannot be seen by Detect Magic, but the aura of Arcane Contradiction can be seen around the creature possessing it at any given time by Detect Magic or similar means, in which case it appears to be Transmutation magic.

You gain one additional use of Distort Arcana per short rest at 15th level, and another at 20th level.

Arcane Contradiction remains active if the owner is incapacitated, but dispels if the owner dies. If the owner of the feat is restored to life but not undeath, then Arcane Contradiction reactivates. If Arcane Contradiction is tied to a different creature than the owner through Distort Arcana and that creature dies, Arcane Contradiction returns to its owner.