There is a Metamagic Feat in Libris Mortis- Fell Animate- that makes creatures slain by a feat-modified spell rise up as zombies, up to 2x caster level in HD of zombies, for +3 spell level.
That would be an ugly way for an Undead Underworld Overlord to beef up his army for short periods of time...especially DURING an attack.
Magic Missile modified with this feat requires 4th level slots, so the boss or his pet spellcaster would have to be a minimum of 8th level arcane spellcaster, resulting in 4 missiles doing an average of 14 points/casting- possibly dropping then instantly animating most low level guards.
OTOH, Burning Hands (available to both arcane & some divine casters) modified with this feat would do an average of 12.5 points/casting...but over a larger area.