Lorloveim's Shadowy Transformation

When this spell is cast, the illusionist transforms one creature or a specified amount of non-living material into shadow, making it insubstantial. Thus, a door could be turned to shadow and entered. The maximum amount of inanimate material that may be transformed is one cubic foot per level of the caster.
Unwilling creatures are allowed a saving throw to resist the shadowy transformation. Magical items and the magical effects of spells (such as Bigby's forceful hand or a wall of stone) cannot be affected.
A transformed creature and all its gear become insubstantial. The creature can pass through small holes, narrow openings, and the smallest cracks. The creature cannot fly without additional magic.
No form of attack is possible when in shadow form except against creatures that exist on the Ethereal plane. In this case, all attacks are normal; however, the shadowy creature may be harmed only by magical weapons of +1 or greater or by creatures able to affect those struck only by magical weapons. Spells and special attacks have normal effects.
Most undead creatures will ignore a creature in shadow form, believing it to be a wraith or spectre; however, liches and powerful undead may save vs. spell with a -4 penalty to recognize the spell. A successful dispel magic spell forces the creature in shadow form back to normal form.

[Tome of Magic]

School: Illusion/Phantasm
Level: 7
Rarity: Rare

Range: Touch
Components: V, S
Duration: 1d4 rounds +1 round/ level
Casting Time: 6
Area of Effect: Special
Saving Throw: Negates