Spell Trap
Abjuration  [Meta-magic]
Level: Sor/Wiz 4
Components: V, S, M
Casting Time: 1 action
Range: Close (25 ft. + 5 ft./2 levels)
Target/Area/Effect: See text
Duration: 1 day/level
Saving Throw: None
Spell Resistance: No
When you cast this spell you create an invisible, magical 'container' which holds another spell. Target this spell at any place within your range that is not occupied by a solid object. Once you have cast this spell you fill the container by casting another spell into it. The trap is now active. The spell container frees the spell it holds when it detects a spell being cast within its detection radius, up to a 5 ft./level radius spread, causing the spell it held to execute. The effects of one spell trap will not set off the effects of another. The spell released from the spell trap is centered upon the trap or strikes outward in a direction specified by the spell-caster at the time of the traps creation.
    A detect magic will reveal the presence of the spell trap, but will give no clue as to the contents of the trap. Of course, casting such a spell may well set the spell trap off if done within the traps detection radius. Creatures affected by the spell released by the spell trap may make save checks as they normally would. The spell trap lasts for 1 day per caster level, or until it is executed. The duration of the spell it holds does not begin until it is released from the spell trap.
    Material Component: A small glass cage which costs 100 gp. Place the cage into the air where you want the spell-trap placed as you cast the spell. The glass cage is consumed in the casting of the spell.