Net of Shadows

(Spell Compendium, p. 147)

Illusion (Shadow) [Darkness]
Level: Sorcerer 1, Wizard 1,
Components: V, S,
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One creature/level, no two of which are more than 25 ft. apart
Duration: 1d6 rounds
Saving Throw: Will negates
Spell Resistance: Yes

You cast the spell, and the surrounding shadows shift at your command, flying toward your targets and wrapping themselves around them.

This spell gives the subjects concealment, but the shifting magic shadows also inhibit the subjects' ability to ascertain their surroundings. The subjects can see only 5 feet through the shadows that coat them, and foes within that range have concealment from the subjects. Darkvision does not penetrate a net of shadows.