Spider Shapes(Spell Compendium, p. 201)
Level: Spider (SpC) 9,
Components: V, S, DF,
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One willing creature/level, all within 30 ft. of each other
Duration: 1 hour/level (D)
Saving Throw: None; see text
Spell Resistance: Yes (harmless)
You channel the power of the spell into the willing masses before you, granting them the blessed forms of spiders.
This spell functions like polymorph (PH 283), except that you polymorph up to one willing creature per level into a monstrous spider (MM 288) of any size from Tiny to Huge as you decide. Unlike with polymorph, this spell allows the subjects to gain a spider's poisonous bite. All the creatures you transmute must become spiders of the same size.
Subjects remain in the spider form until the spell expires or you dismiss the spell for all subjects. In addition, an individual subject can choose to resume its normal form as a full-round action. Doing so ends the spell for that creature only.