Suffocate

This spell draws the breath out of all creatures within the area of effect who fail a saving throw. Their breath is placed within a small silk bag held by the caster.
Each round, a victim of this spell must attempt a Constitution check. If failed, the creature suffers 2d4 points of damage. If successful, the subject has taken in enough air to reduce the damage to 1d4.
As they struggle and gasp for air, affected creatures move and attack at half their normal rates, have a -4 Armor Class penalty, an attack penalty of -4, and lose all Dexterity combat bonuses.
Effects of this spell continue each round regardless of whether the victims remain in the original area of effect. The damage accumulates until the spell expires, the silk bag is opened, or a successful dispel magic spell is cast upon the bag. The penalties to combat remain in effect for 1d3 rounds after the spell ends.
The material component bag is not destroyed during casting, but becomes useless for future castings if a successful dispel magic spell is used on it.

[Tome of Magic]

School: Alteration, Necromancy
Level: 7
Rarity: Uncommon

Range: 30 yards
Components: V, S, M
Duration: 1 round/level
Casting Time: 7
Area of Effect: 10-foot-radius circle
Saving Throw: Negates

Material Components:
a small silk bag studded with black opals worth a total of no less than 5,000 gp