Overspell

Transcendence

When you cast a leveled spell, you can treat the spell as if it were cast using a higher level spell slot than you used. You can increase the slot level by a number up to half your proficiency bonus. In this way, you can also cast higher level spells with lower level spell slots.   When you use this ability, roll a hit die. You lose a number of hit points equal to your roll and your hit point maximum is lowered by the same amount.   The number of dice you roll increases by 1 for every time this ability is used. Your hp max and number of dice rolled both reset when you finish a long rest.