Enhanced Fireball

A bright streak flashes from your pointing finger to a point you choose within range and then blossoms with a low roar into an explosion of flame. A target takes 10d8 fire damage on a hit and 20d8 damage on a crit.

if a creature moves through the area and doesn't have immunity to fire damage they stop immediately and take 1d8 fire damage for each round they are in there and fall unconscious.

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

if any monster moves within the area it takes 2d6 fire damage per round that it stays in the area

Once it hits the ground the ruby and Fire opal dissipate into ash.