A jet of black, writhing, and howling fire erupts from your hands in a 60 ft line consuming all in its path. At the end of the 60 ft line the flames explode into a 10 ft wide and 10ft tall cylinder of flame. Any creature in the line or cylinder must succeed on a Dexterity saving throw. On a failed save the creature takes 10d8 fire damage and half that on a successful save.
The black flames then take on a life of their own and you then must roll 1d8 to determine the chaotic effect that occurs:
1: The black fire, angered at being summoned, lashes out. The cylinder of fire expands to a 20 ft radius and 20 ft height effecting every creature in that area the same way the spell normally would.
2: The caster of the spell receives some blow back from the intense heat and takes 4d8 fire damage.
3: The black fire attempts to consume the creatures in its path. Anything struck by the spell originally, has fire wrap around their bodies dealing 2d6 fire damage at the start of each of their turns for 3 rounds. This effect can only be removed early with a Remove Curse Spell.
4: The black fire spreads around the room regardless of the rooms size and all flammable objects in the room are ignited. The intense heat deals 1d6 fire damage to everything in the room.
5: The black fire gathers together becoming a Fire Elemental. The Fire Elemental lasts for one minute and takes commands from the caster of the spell as if the the caster had cast Conjure Elemental.
6: The black fire gathers together becoming a Fire Elemental. The Fire Elemental lasts for one minute. The only goal of the elemental is to destroy the caster of the spell. It will do everything in its power to do so. If the caster dies the fire elemental dissipates.
7: The intense heat lowers the AC of all affected creatures by 2.
8: The black fire burns a hole into a realm of chaos and destruction centered on the point of the cylindrical portion of the spell. This portal now has an initiative count 15 (losing on ties). Any large or smaller creature within 10 ft. of this portal on initiative count 15 must make a DC 16 Strength saving throw or be sucked into the portal and banished to the realm of chaos. Once a creature is sent through the portal, the portal closes.
* - (A vial of blood from any Devil)