Dance of the Spider p. 76
Black, shadowy energy covers your hands and feet, allowing you to scuttle across the walls and ceiling like a lurking spider.
While you are in this stance, you gain a benefit similar to the spider climb spell (PH 283). You gain a climb speed of 20 feet. You do not need to make a Climb check to traverse a vertical or horizontal surface, even if you attempt to move across a ceiling. You retain your Dexterity bonus to AC while climbing, and you must have at least one hand free to support yourself while you climb. You take no penalties for climbing in this way, but other penalties can still apply. Likewise, enemies still gain bonuses for attacking you, unless those bonuses are because you are climbing. You cannot take a run action while climbing in this manner.
This maneuver is a supernatural ability.