Blade Barrier

You create a wall of whirling blades made of magical energy. The wall appears within range and lasts for the duration. You make a straight wall up to 100 feet long, 20 feet high, and 5 feet thick, or a ringed wall up to 60 feet in diameter, 20 feet high, and 5 feet thick. The wall provides Three-Quarters Cover, and its space is Difficult Terrain.

Any creature in the wall's space makes a Dexterity saving throw, taking 6d10 Force damage on a failed save or half as much damage on a successful one. A creature also makes that save if it enters the wall's space or ends it turn there. A creature makes that save only once per turn.