The simplest of things to be explained, the Amnionic Universe or Amnionic Dominion is the entirety of the normal universe, including Earth, the solar system, the Milky Way, and so on. Things cannot physically go through the barrier around the Amnionic Universe and the rest of known reality, there are plenty of known magical summoning or teleportation maneuvers that could land one on either side, but there is no way to physically go through the wall.