Greater Binding Working Draft
Binding Cage
 Conjuration (Summoning)
Level: Goat 6, Sor/Wiz 7
Components: V, S
Casting Time: 1 minute
Area: A circle with a radius up to 5 ft. per 2 levels
Duration: 1 week/level (plus see below)
Saving Throw: Will negates (see below)
Spell Resistance: No
This spell creates an invisible magical trap that can restrain an undead  creature or a creature with the Extraplanar subtype. The caster must  trace out a circle and mark it with runes that identify what creature  the binding cage will trap, either by type, subtype, species,  or truename (e.g. "Undead", "Tanar'ri", "Lantern Archon", or "Rexpluff  the Dust Mephit"). The circle and its runes are clearly visible to any  creature using see invisibility, arcane sight or true seeing.
The binding cage is triggered when a creature that matches the rune identification attempts to exit the circle. A binding cage  can trap multiple creatures with the same identification if they are  all within the circle when it triggers. When triggered, an invisible spherical cage of force appears that encompasses the circle and all creatures within it. In addition, the triggering  creatures must succeed at a Will save or be shackled by magically conjured chains. If the binding cage's caster level is more than twice the Hit Dice of a triggering creature, it increases the save DC by 2.
Victims shackled by the chains are fixed to the space they are in, but   can still act.  The chains  are impervious to magic and all types of  energy damage, prevent dimensional  travel of any kind, and can restrain  a victim regardless of its shape,  substance, or plane of existence -  meaning a victim cannot escape by  using teleportation, shapechanging,  etherealness or gaseous form  abilities.
A victim can only escape the chains by sheer brute force. The chains can  be shattered with a Strength check (Break DC equals caster level plus  12) or a single attack   that inflicts damage that's at least twice the  caster level. If the chains are broken they vanish instantly but the  victim is still confined within the cage of force, which remains for the  duration of the binding cage spell.
The spherical cage of force has the same properties as the barred form of a forcecage spell, except its bars are far enough apart to allow the passage of creatures of Tiny size or smaller.
A binding cage is immune to dispel magic. A disintegrate spell can destroy all or part of the cage of force, but cannot affect the chains. The spherical cage of force vanishes when the spell's duration expires, but the magical chains remain and continue to restrain their victims for another 1 week per caster level (so the chains have a total duration of 2 weeks per level). The continued existence of the chains allows a spellcaster to place a new binding cage around the shackled victim to replace an binding cage whose duration has expired.
A binding cage is only be triggered once. Other creatures of  the specified target class that enter and exit the circle after it is triggered will not be shackled.
The chains of a binding cage can be made permanent with a permanency spell at a cost of 3,000 XP. The cage of force aspect of the spell still has its normal duration.
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