Calamitus Clap

You target 1 creature you can see within range that you've dealt 100 or more damage to in a single hit. You clap your hands together, shattering the diamonds and scattering them in a 30 foot sphere. The pieces come together to then form a beam of light from your hands to the creature, which destroys the energy that created its existence. Immediately after casting, you take 5 points of exhaustion and go down to 1 hit point.