Chariot of Sustarre

A large, flaming chariot pulled by two fiery horses appears in a clap of thunder with cloud-like smoke. The steeds can be commanded verbally to walk, trot, run, fly, or turn as the caster desires. It moves at 50ft on the ground, and 100ft flying, and the caster can designate up to 8 other human-sized passengers to ride along with them. Creatures other than the caster and their passengers within 10ft of the chariot or horses must succeed a constitution saving throw or take fire damage, and half damage on a success - the fire inflicts 4d4+7 points of fire damage. Undead always take double damage, and creatures vulnerable to fire may take extra damage as well. 

The chariot and steeds are physical, and can sustain damage. One quart of water causes 1 hp damage, and the chariot or steeds, and they can also be struck by magical weapons. They are AC 2 and have 30 hp. Fire doesn't affect the chariot or the steeds, but it may affect the riders. The chariot and steeds shed bright light out to 30ft, and dim light an additional 30ft.

DM's Advice: The entities called by this spell are beings of elemental fire, and so can be returned to their home plane with spells that do so.