Death Ball

You raise your hands above you and gather magical energy over your head for the next minute, not doing anything else besides focusing on the spell (cannot move, take actions, bonus actions, or reaction). Over the following minute, a ball of destructive magic forms and grows into a 40-foot radius sphere which must be thrown once fully formed. Once thrown, the death ball cannot be stopped by anything other than a wish spell as it travels in the direction thrown at a rate of 60 feet at the start of your turn.

If a creature is hit by the death ball during its journey, it must make a Dexterity saving throw or become swallowed into the ball. Whilst trapped in the ball the creature is considered grappled and must make a Strength saving throw at the start of its turn to escape. On a failure, the creature takes 35 (10d6) force damage and travels with the death ball. On a success, the creature takes half damage and escapes the death ball, appearing in the nearest unoccupied space out of the path of the death ball.

Once the death ball collides with a suitable surface, it detonates in a 150-foot radius sphere. All creatures in the area must make a Consution saving throw, creature trapped by the ball making the save at disadvantage. On a failure, the creature takes 220 (40d10) force damage and is knocked prone. A creature that fails the save by 5 or more is also stunned for 1 minute. On a success, the creature takes half damage. Structures take double the damage and if the damage kills a creature, it and any non-magical equipment it is carrying are turned to ash.

If the caster is hit before the full minute has passed they must make a Constitution saving throw to maintain concentration. On a failure, the caster must throw the ball prematurely, following the rules mentioned above except the damage changes depending on the number of rounds the death ball has been charging for.