Combusting Critical (5e Feat)
From D&D Wiki
Your critical hits spark magical explosions. You gain the following benefits
- You learn the green-flame blade cantrip.
- When you cast green-flame blade, you score a critical hit on a roll of 19 or 20.
- When you score a critical with the green-flame blade cantrip, you deal additional damage equal to 1d8 fire to each target.