Boon of The Great Toad

The Great Toad, Krawoaka, has granted you a lesser boon, it's power surging through you, a power that can be channelled to protect yourself or others. 

Your Constitution score increases by 1. In addition, once a day, when you or a creature you can see within 30 feet of you suffers a critical hit, you can use your reaction to expend your single charge to turn the critical hit into a normal hit instead. This ability recharges upon the next dawn.