Sudden Stampede

You conjure up a multitude of fey spirits that manifest as galloping horses. These horses run in a 10-foot'wide, 60-foot-long line, in a given direction starting from a point within range, trampling all creatures in their path, before vanishing again. Each creature in the line takes 6d10 bludgeoning damage and is knocked prone. A successful Dexterity saving throw reduces the damage by half, and the creature is not knocked prone.