Abjuration
Level: Cleric 4, Portal 3, Sentinel 4, Sorcerer 4, Wizard 4
Components: V, S
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Effect: Ray
Duration: 1 minute/level
Saving Throw: None
Spell Resistance: Yes (object)
A green ray springs from your outstretched hand. You must make a ranged touch attack to hit the target. Any creature or object struck by the ray is covered with a shimmering emerald field that completely blocks extra-dimensional travel. Forms of movement barred by a dimensional anchor include astral projection, blink, dimension door, ethereal jaunt, etherealness, gate, maze, plane shift, shadow walk, teleport and similar spell-like or psionic abilities. The spell also prevents the use of a gate or teleportation circle for the duration of the spell.
A dimensional anchor does not interfere with the movement of creatures already in ethereal or astral form when the spell is cast, nor does it block extra-dimensional perception or attack forms, such as a basilisk’s gaze. Also, dimensional anchor does not prevent summoned creatures from disappearing at the end of a summoning spell.
Source: Player’s Handbook (Page 221)