Bluefire strike

This spell summons a blue ball of Fire that reeks of hell, where ever it strikes will scorch the earth in a 20ft radius of Fire on the ground
this spell does 4d10 Fire damage every round , half as much on a successful Con save (15 to succeed)

after the 5 rounds the fire dissipates 
This fire will harm everyone within its radius unless they are immune to fire , friendly players included