Sorcerer/14th

Overcharge

Starting from 14th level, when you cast a powered sorcerer spell of 5-points or fewer that deals damage, you can deal maximum damage with that spell. Instead of rolling the dice, you add together the maximum amount of all dice that would otherwise be rolled.

The first time you do so, you suffer no adverse effect. If you use this feature again before you finish a long rest, you take 1d12 psychic damage for each magic point of the spell, immediately after you cast it. Each time you use this feature again before finishing a long rest, the psychic damage per point increases by 1d12. This damage ignores resistance, reduction, and immunity.