Asphyxiate

This spell asphyxiates individuals (chosen by the priest) who fail a saving throw vs. death magic. If fewer than six individuals are targeted with this spell, each receives a -1 penalty on their save (-2 for three creatures or less, -4 if the entire spell is focused on a single creature). This necromancy induces a victim's throat to constrict and his or her lungs to swell shut, similar to a severe allergic reaction, for so long as the subject remains within range of the spell.
Each round, a victim must attempt a Constitution check. If failed, the victim suffers 1-6 points of damage. If successful, the subject manages to gasp in enough air to reduce the damage to 1-3 points. During its struggles against asphyxiation, the affected creature becomes effectively slowed (as per the 3rd-level wizard spell). A victim who fails three consecutive Constitution checks has been smothered and dies automatically on the following round.
The effects of asphyxiate continue until either the spell expires, a victim withdraws beyond range of the spell, or a successful dispel magic is employed on a victim. Victims remain slowed for 1-3 rounds after the spell ends. This spell normally affects only humans or demihumans, though the DM may extend the dominion of the spell to include man-sized or smaller animals and monsters. Obviously, creatures (such as undead and plant creatures) that never breathe cannot be affected by this spell.
The priest loosely wraps the silken gag around his or her own mouth after casting the spell. Because of its murderous effect, asphyxiate is typically granted only to priests serving evil deities.

[Complete Book of Necromancers]

Sphere: Necromantic
(Necromancy)
Level: 6
Restrictions: Death Priests only

Range: 120 yards
Components: V, S, M
Duration: 1 round/ level
Casting Time: 9
Area of Effect: One individual/two levels
Saving Throw: Negates

Material Components:
an unholy symbol and a silken gag