The container

The Container is an absolutely enormous structure that has a special quality that determines its name: It contains literally EVERY object that is smaller than itself, (that is, almost all Class 21's and below). The one exception to this are objects that are contained in the Super Container solely, which are few and far between, and other containers in the Super Container. This makes only 6.98×10-16% of the mass of the Super Container that is not contained by a Container.
While to beings smaller than it, the Container appears opaque, but in fact it is see-through to beings larger then TSC. For civilisations that are able to escape other Class 21 bodies, escaping the Container is actually trivial. Poking a hole in one, is much harder, and will actually dissolve the entire container, like shattering glass or a balloon popping. Only beings larger than the TSC can do this. However, maybe an extremely dedicated Post-TSC might be able to do this, but this is unlikely, as it requires tremendous force.
Due to the container containing every Class 21 and below object at least once (probably an understatement, it contains immesurable amounts of each), it is one of the verses with the biggest EUSI. Yet another reason why I will not count it all out. The container is seen by all sub-TSC beings to be black, despite not actually having color. The cause of this is not yet known. 
Category:Idontknow's pages
Category:Verse
Category:Structure
Category:Container Chain
Category:21th-class
Category:Fish's pages
Category:Fish’s Early Pages
Category:Post-Alphasm
Category:Navigable