Self Destructive

When a wizard gets backed into a corner the possibility of exerting too much magic becomes a possibility. By being self-destructive, a wizard can cast spells by the following:

• If the wizard has access to the level of spell slots but has used them all, they can take a level of exhaustion to cast the spell anyway.
• If the wizard's spellbook has spells of a higher spell slot then their highest spell slot, they still use it by taking two levels of exhaustion for the first level and an additional level of exhaustion for each level after. Exhaustion takes effect after the spell goes off, after the hit roll, and spells over five levels the casters max spell slot will die after the spell goes off.

Examples: 6th level Wizard player finds a spellbook with Power Word Pain, the wizard would be able to use it, most likely in an emergency, if they take five levels of exhaustion putting them near the brink of death. However, the same wizard would be able to use Fireball after they have used up all of their 3rd level spell slots at the cost of one level of exhaustion every time they use a spell without spell slots.