Brick Ward

As an action, a creature can cast this spell, causing a colorful, diverse splattering of bricks to appear on the ground within 40ft of the caster. The ward takes up a space of 15ft by 15ft square zone and can go around corners. A creature that starts its turn or attempts to move through the smattering of bricks must make a constitution save or take 3d10 piercing damage, or half as much on a save. The spell lasts for three rounds or until dispelled, and the affected zone is considered difficult terrain.