Destructive Vortex

You summon a large 15 radius vortex in a place within range.

Any creature that is in the spell radius must make a Dex saving throw, on a fail they take 5d8 bludgeoning damage and are knocked prone and be dragged to the middle of vortex of two or more creatures fail this save and are dragged to the middle that all take an extra 1d8 bludgeoning damage, on a save that take half damage arn’t knocked prone or dragged to the middle. 
Any creature inside the vortex take double movement to get out as it is classified as different terrain