Blind Ambush

You blow on a whistle, releasing an inaudible sound. Choose a point on the ground within range. The first time a creature moves while within a 10-foot square centered on that point before the spell ends, an eldritch maw immediately erupts from beneath the ground, dealing 2d10 piercing damage to each creature within the square and knocking them prone. The spell then ends.
At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d10 for each slot level above 2nd. When you cast this spell using a spell slot of 5th level or higher, the spell can trigger a second time before it ends.