Field of Ghouls

(Libris Mortis: The Book of the Dead)

Necromancy [Death, Evil]
Level: Hunger 7,
Components: V, S,
Casting Time: 1 standard action
Range: Personal
Target: 30-ft.-radius spherical emanation, centered on you
Duration: 1 round/level
Saving Throw: Will negates
Spell Resistance: Yes

You transform the ebbing life force of all nearby badly wounded creatures and use it to create ghouls.
Upon casting this spell, you radiate a necroconsumptive death field.
All creatures in the area with fewer than 0 hit points that fail their saving throws die, and immediately rise as ghouls under your control.
The ghouls follow you, or can remain where formed and attack any creature (or just a specific kind of creature) the ghoul notices.
The ghouls remain until they are destroyed.
The ghouls that you create remain under your control indefinitely.
No matter how many ghouls you generate with this spell, however, you can control only 2 HD worth of undead creatures per caster level (this includes undead from all sources under your control).
If you exceed this number, all the newly created creatures fall under your control, and any excess undead from previous castings become uncontrolled (you choose which creatures are released).
If you are a cleric, any undead you might command by virtue of your power to command or rebuke undead do not count toward the limit.
Creatures that fall to -1 hit points or fewer in the area after the spell is cast are likewise subject to its effect.
No creature can be affected by this spell more than once per round, regardless of the number of times that the area of the spell passes over them.