Source: Arcana Unleashed
Level 9 Evocation (Sorcerer, Warlock, Wizard)
Casting Time: Action
Range: 500 feet
Components: V, S, M (a piece of tinder)
Duration: Instantaneous
You create a magical, explosive seed inside a creature you can see within range. The target makes a Constitution saving throw, taking 10d10 Fire damage on a failed save or half as much damage on a successful one.
An explosion then originates from the target. Each creature in a 60-foot Emanation originating from the target (not including the target) makes a Dexterity saving throw, with Disadvantage if this spell reduced the target to 0 Hit Points. A creature takes 10d10 Fire damage on a failed save or half as much damage on a successful one.
A nonmagical object that isn’t being worn or carried also takes the damage if it’s in the Emanation, and the object starts burning if it’s flammable.