Normal: You alter the fabric of dimensions, making extraplanar travel impossible. A creature who attempts to leave is briefly surrounded by a blue nimbus and finds - probably to its surprise - that it hasn't gone anywhere.

This duplicates the effects of the dimensional lock spell.

Reverse: A blue nimbus surrounds all creatures in the area, pushing them out of this plane.

You force all occupants of the area into a plane of your choice, where they remain for the duration. Once the duration expires, they return to their original location, or as close as possible, even if they are dead. If they are unable to undergo planar travel when the duration expires, they remain in the plane to which they were sent.