Wraithform

Wraithform  3rd-level transmutation  [Wizard’s Spell Compendium 2e] [Sor War Wiz]

You gain the Incorporeal Movement trait (see Wraith, MM, p302). You can move through creatures or objects as if they were difficult terrain. If you end your turn inside a creature or object, you take 1d10 force damage. You also have immunity to necrotic and poison damage and resistance to acid, cold, fire, lightning, and thunder damage, and to bludgeoning, piercing, and slashing damage from weapons that aren’t silvered.

In addition, you can’t hold or use weapons or benefit from armor and shields for the duration. Your AC equals 10 + your Dexterity bonus. On each of your turns, you can use your Action to make a melee spell attack against a creature within reach. On a hit, the creature takes necrotic damage equal to 2d8 + your spellcasting ability modifier.

At higher levels: When you cast this spell using a spell slot of 5th level or higher, the necrotic damage increases by 1d8 for every two slot levels above 3rd.