Contagious Flame

This spell is an improved version of Immolation.  Flames wreathe one creature you can see within range. The target must make a Dexterity saving throw. It takes 8d8 fire damage on a failed save, or half as much damage on a successful one. On a failed save, the target also burns for the spell’s duration. The burning target sheds bright light in a 30-foot radius and dim light for an additional 30 feet. At the end of each of its turns, the target repeats the saving throw. It takes 4d6 fire damage on a failed save, and the spell ends for that target on a successful one. These magical flames can’t be extinguished by nonmagical means, but the caster can cancel the spell at any time.

At the end of each consecutive round, regardless of the initial target's save, all creatures within 5 feet of the affected target must make the same saving throw or be affected as well.  This effect repeats itself every round for one minute.  After each consecutive round, all allies of the affected targets (regardless of saves) must make a Wisdom saving throw or become afraid at seeing their comrades burst into flame.  A failed save sends them fleeing away in fear from the flames at full speed for the duration of the spell.

If damage from this spell kills a target, the target is turned to ash.