For those Underlords that prefer the illusion of security more than is actual existence the Illusory Wall is a gift sent from a particularly generous omnipotent being. Once cast the illusory wall will remain completely fixed in place for a period of time before wandering back to where it came from; if a worker so much as coughs next to it the illusion will be dispelled.
Illusory Wall is one of the spells available within the Vein of Sloth.