7th-Circle Primordial (Transmutation)
Casting Time: 1 action
Range: 90 feet
Components: V, S, M (an ivory war horn or set of pipes worth at least 500 gp)
Duration: 1 minute
You stir the air to create four whirlwinds on the ground at points you can see within range. Each whirlwind is a 5-foot-radius, 30-foot-tall cylinder of swirling air centered on that point. The whirlwinds last for the duration of the spell.
Each creature that enters a space occupied by a whirlwind for the first time on a turn (including when the whirlwinds first appear) or starts its turn in a space occupied by a whirlwind must make a STR save. On a failed save, a Large or smaller creature takes 4d10 bludgeoning damage and is thrown up to 60 feet in a random direction and knocked prone. On a failed save, a Huge or larger creature takes the bludgeoning damage and is not thrown but is restrained until the beginning of its next turn. On a successful save, creatures of any size take only half as much damage and are pushed out of the whirlwind into a random unoccupied space within 5 feet of the whirlwind.
If a thrown creature strikes a solid surface, it takes 1d6 bludgeoning damage for every 10 feet it is thrown. If the creature is thrown at another creature, the hit creature must succeed on a DEX save against your spell save DC or take the same damage as the thrown creature and be knocked prone. If a thrown creature is thrown into another whirlwind, it is then thrown from the new whirlwind up to 60 feet again in a random direction.
At the start of each of your turns after the whirlwinds first appear, you can use your action to control them, moving each one up to 30 feet in a direction you choose. If you can’t use your action or choose not to use your action to control the whirlwinds, each whirlwind moves up to 30 feet in a random direction, potentially affecting you along with any other creatures it encounters. If multiple whirlwinds would end their turn in the same space or overlapping spaces, one whirlwind moves to the space, and the other moves to the nearest adjacent space not occupied by a whirlwind.
You can use an action to end the spell early, which causes the whirlwinds to disappear. The spell also ends early if you are incapacitated or die.