Torubarrier

The torubarrier is an extremely large barrier that contains one Metatoriverse. It is not green like the picture shows, there's no light emitted by it so it looks invisible.

The image of the torubarrier is actually taken with a special camera.

Getting past the barrier
The torubarrier, while large, is very thin. It is made of a material that we currently do not think can be broken, because we haven't been able to take a sample to examine it.

It is possible to get past the torubarrier, though. Currently, there's a wormhole that goes to the other edge of the torubarrier. This happened because quantum teleportation is very common outside Metatoriverses when inside a torubarrier, and one side of a wormhole quantum teleported out of the torubarrier. This is the only known way to get past the torubarrier.

Different Shapes
Very rarely, Torubarriers can be other shapes than hyperspheres.