The superverse in Best's Cosmoline is seen as a large maze-like pit with no way out, and every dead end, there is a Multiverse. At the floor, there is a very corrosive substance that will turn anything into the substance other than the multiverses and the maze walls. If any entity comes in here, the substance will rise over the span of a month until the entity is destroyed, and then the substance will lower again. Not really anything else to say.