Subspace

Subspace is an alternate dimension within Subcon in Super Mario Bros. 2. They are only accessible by using a Magic Potion to create a door that leads to Subspace. Subspace consists of a single-screen mirrored area from where the door was entered, and it has pitch black terrain with no enemies. Plucking a patch of grass always results in obtaining a coin. After a few seconds, the playable character is forced back into the main level.
de:Unterwelt
it:Subspazio (Super Mario Bros. 2)
Category:Super Mario Bros. 2