Pohldahk
The entity: Unrevealed, definitely a dimension called the Plane of Pohldahk, but whether there is an entity other than the dimension being entreated is unknown.
The spells: "Planes of Pohidahk." A dangerous spell which requires great concentration (no possible disturbances), time (3 rounds), knowledge (spell only found in a scroll or tome), and a successful Psyche FEAT roll by the caster. The spell turns the target into a 2-dimensional state, somewhat like a reflection of someone in a mirror. If the plane of the target is shattered, the target is destroyed.