Bonfire of Insanity

While casting the spell, you create a bonfire from humanoid remains and set fire to it during a rainstorm. The rain doesn't extinguish the bonfire until the material components are consumed. The smoke from the pyre fills the rain clouds with unholy power. As the tainted water rains down it tears seep into their minds. Any creatures within 30ft of the rain must make an Intelligence saving throw. If the creature fails they take 8d8 necrotic damage & gain madness; on a success, they only take half of the damage.