You conjure a sphere of magical ruby that is 1 foot in diameter in an unoccupied space of your choice within range. This sphere stays in place, even if in the air. The spell ends if the sphere is moved more than 1 feet from its original position which requires a Strength (Athletics) check with a DC equal to your spell save DC. The sphere has an AC of 15 and it has 10 hit points. If the sphere is ever reduced to 0 hit points the spell ends. The spell also ends if you are ever more than 150 ft from the sphere.

When the spell ends the sphere explodes in a burst of ruby red energy out to a range of 40 feet in radius. All creatures within the range of this explosion receive 1d4 force damage (there is no saving throw). On your turns, except the turn on which you cast this spell, while the spell is in effect and not yet ended you can spend an action to boost the damage: each time you do the damage increases by an additional 1d4, up to a maximum of 100d4. Objects and structures caught in the blast receive double damage. If this spell is ended due to Dispel Magic it ends without explosion.