Selective Snare

House Dimir Spell
Level 4
Casting Time: 10 Minutes
Duration: 24 Hr
Range: 30 ft
Choose a Creature Type and an area in range that is no larger than a 20-foot cube. You can choose when to end this spell and can do so as a free action. While this spell is active, you have knowledge when creatures of the chosen type enter and leave the area; you know how many are within it at all times, but only creatures of the chosen type. When the spell ends, the trap triggers and creatures of the chosen type (size Large or Smaller) within range must make a CON Save or become Paralyzed (?), they can repeat this save at the end of each of their turns but it only ends on a success. When you cast the spell, you can designate creatures that won't be selected by the trap.