A beam of yellow light flashes from your pointing finger, condensing to linger at a chosen point as a glowing bead... ready to be detonated at a moment's notice.

When the spell ends, either because your concentration is broken or because you decide to end it, the bead blossoms with a low roar into an explosion of flame that spreads around corners. Each creature in a 8m radius sphere centered on that point must make a

The spell's base damage is 10d8. If at the end of your turn the bead has not yet detonated, the damage increases by 1d8, and the radius increases by 2m, to a maximum of 20m. If the glowing bead is touched before the interval has expired, the creature touching it must make a Dexterity saving throw. On a failed save, the spell ends immediately, causing the bead to erupt in flame. On a successful save, the creature can throw the bead up to 14m. When it strikes a creature or a solid object, the spell ends, and the bead explodes.

The fire damages objects in the area and ignites flammable objects that aren't being worn or carried. You can end this spell harmlessly as an action.

At Higher Levels: For each spell level increase, the base damage increases by 1d8.