Calcifer’s Climacteric

You channel raw elemental arcane power and instill it in a willing creature you can see within range.

Until the spell ends, all attacks made by the affected creature score a critical hit on a roll of 19 or 20.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the minimum roll required to score a critical hit reduces by one for every two slot levels above 3rd.