Ethereal Fog

Ethereal fog is a shimmering mist which manifests suddenly and out of thin air. It obscures all sight, including darkvision, beyond 5 feet. Creatures 5 feet away have concealment (attacks by or against them have a 20% miss chance). In addition, creatures taking a movement action within the fog must succeed on a DC 15 Wisdom save or be teleported to a different random location within the fog.