Enhance Spell

You attempt to imbue additional magic into the casting of a spell within 30 feet of you. When you cast this spell, you can attempt to contribute any amount of additional levels of spell slot you have available to the casting of the spell. You must make a Constitution saving throw equal to 10 +  the amount of spell levels you are attempting to contribute. On a failed save, your contribution is unsuccessful and you gain a level of exhaustion. On a success, treat the triggering spells' level as the combination of the original level it was cast at plus the amount of levels contributed.

This effect cannot bring the total level of the spell above 9th level.