Channel Fireball

Roll any number of your hit dice, choose a point within range and channel a fireball that causes every creature within a 20 foot sphere centered on that point to make a Dexterity saving throw of 18. On a failed save each creature takes the amount of damage equal to the rolled hit dice. On a successful save that creature takes half. You then take that amount of Psychic damage in any instance. You do not gain those hit dice back until after you complete a long rest. If you fall to zero hit points as a result of this you immediately are dealt 2 failed death saving throws. 

The fire spreads around corners. It ignites flammable objects in the area that aren’t being worn or carried.

Magic the Gathering.