Black Flame Ritual

You summon black flame in a ring around you in a 10-foot radius. The black flame remains until the end of your next turn. Each creature other than you that enters the area for the first time on a turn or starts its turn there takes 4d6 fire damage and is set alight with black flame for the duration.
While alight, a creature takes fire damage equal to half of its level or CR (whichever is applicable) at the start of each of its turns. The target or another creature can use its action to put out the fire.
At Higher Levels.
When you cast this spell using a spell slot of 7th level or higher, the damage increases by 1d6 for each slot level above 6th.