Crystal Eruption

You cause crystal spikes to burst from the inside of a creature that you can see within range, causing it searing pain. The target must make a Constitution saving throw. It takes 4d6 + 50 piercing damage on a failed save, or half as much damage on a successful one.

Creatures killed with this spell become consumed by the crystal until they are completely encased in it. After 1 minute, or if the caster chooses to, the crystal covered corpse explodes dealing 8d8 piercing damage to a 30 foot cube. Anyone caught in the explosion can make a dexterity saving throw to take 1/2 damage.

The crystal spikes last 1 minute then shatter into fine crystal dust and disappear.