You make the sign of Yrden causing a ring of glyphs of purple light to appear at your feet.  The ring is 10ft in diameter and does not move with the caster.  If a creature other than you enters the ring they must make a DC 12 CON save or suffer from the following conditions.  The creature's speed is halved, AC reduced by 2 and it makes DEX saves at disadvantage.  A creature affected by these conditions loses them immediately upon exiting the ring.  If the creature succeeds on the save they are unaffected by the ring for the rest of its duration.  The ring persists until the end of your next turn when it disappears completely.