Delayed Cone of Cold

A beam of light blue light flashes from your pointing finger, then condenses to levitate in front of you as a glowing bead for the duration. 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 freezing cold air that erupts into a 60 foot cone in front of you. Each creature in the cone must make a Constitution saving throw. A creature takes cold damage equal to the total accumulated damage on a failed save, or half as much damage on a successful one.

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.

A creature killed by this spell becomes a frozen statue until it thaws.

At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, the base damage increases by 1d8 for each slot level above 7th.