The Raging Moon Beam

When the Full Moon appears, you´ll be able to cast "The Raging Moon Beam" if 3 or more people has this spell. This spell makes an enormous light 300ft to 900ft from you, that explodes 4 times in 50 sec. The people or creature that are in the light zone, must make a Constitution saving throw to receive half of the damage . If it fails, who´s in that zone will take 10d12 of damage. "The Raging Moon Beam" will cost 4 spell slots and 3 levels of exhaustion for the one´s who cast this spell