Teclis' Fiery Convocation

A tremendous phoenix made up of flames rises above your head and flies toward a point you chose within range burning everything within a 15ft path along the way. Each creature in the area must make a Dexterity saving throw. It takes 5d8 fire damage and 4d8 radiant damage on a failed save, or half as much on a successful one.
At the end of its flight the phoenixflames die down and shrink in to a sphere that sits in a 5ft cube at the end of the phoenix' path. A creature that passes through the spheres space or starts its turn inside it must make a dexterity saving throw or take 3d8 fire damage on a failed save, or half as much on a successful one.

Rebirth
On subsequent turns you may choose to unleash the flames within the sphere as an action. The phoenix reawakens and unleashes a barrage of projectiles while flying up in the air. Choose a number of creatures within range equal to 3 + (the number of turns you spent concentrating on the sphere) from the phoenix' position. On a failed save a creature takes 4d12 fire damage, or half as much on a successful one.
You may forego attacking creatures with the projectiles and instead shoot your allies to heal them with the phoenix' cleansing fire. Each ally hit a projectile of the phoenix' rebirth is healed for 4d12 health, but can only benefit from one projectile per cast of this spell.
The spell then ends and the phoenix fades out of existence.