Azol's Burning Wreath

You create colored cinders, sparks, or flames in a 10-foot Emanation centered on yourself for the duration, granting the following benefits:

• Creatures in the Emanation have Resistance to Cold damage.
• Any ranged weapon attack that passes through the spell's area is made with Disadvantage. On a miss, a thrown weapon begins Burning, and a piece of ammunition is destroyed. On a Critical Hit, the attack deals an additional 4d8 Fire damage.
• Whenever another creature enters the spell's area for the first time on its turn or starts its turn there, you can force it to make a Dexterity saving throw. On a failure, the creature takes 4d8 Fire damage and begins Burning. On a success, a creature takes half as much damage only.
• Once before the spell ends, when you deal damage to one or more creatures, you can deal an additional 4d8 Fire damage to each of those creatures. The spell then ends.

Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 4. With a level 8+ spell slot, creatures gain Immunity, rather than Resistance.