Lightning Focus (5e Feat)
From D&D Wiki
Prerequisites: The ability to cast at least one spell
After a spell went awry, the magical charge in the air attracted a thunderstorm. After the incident you discovered your misadventure had benefits.
- You have immunity to lightning damage.
- Due to the current now permanently coursing through you, you may add 1d8 lightning damage to your total damage on a critical roll.