Phase trap

Phase trap was an arcane alteration spell that could temporarily anchor a plane-hopping creature to the Prime Material Plane.

Effects
The caster of phase trap was required to be within 20 yd (18.3 m) and have direct line of sight to the target. If the creature resisted the magic of this spell, then it had no effect. Otherwise, the target was locked to the Prime Material Plane for a number of minutes equal to the experience level of the caster. Magic items that performed the same type of phasing between planes also ceased to function. However, spells that were more advanced than this spell, such as the 5th level phase door spell, were unaffected by phase trap.

Specific Effects
Phase trap was particularly good at preventing Ethereal Plane travel but had a chance to prevent Astral Plane travel as well. Creatures that phased through solid objects were also special cases. See below.


 * Creatures such as blink dogs, displacer beasts, and phase spiders could not use their ability while under the effects of this spell.
 * Creatures such as xorn that phased through solid matter were prevented from doing so for the duration of this spell. In addition, if they were inside something solid when the spell took effect, they suffered significant damage until they managed to extricate themselves.
 * Spells of 4th level or lower fizzled upon casting or immediately ceased functioning: blink would be impossible and a person using rope trick would be dumped back onto the Prime Material Plane.
 * Magic items, such as oil of etherealness or a portable hole, could not be used by a person under the effects of phase trap.

Components
In addition to verbal and somatic components, this spell required a clear gem of at least 50 gp in value that was consumed in the casting.

History
This spell was published in "Volo's Guide to All Things Magical" and became generally known to the magical community.