The unreconstructed Lister from the "main" universe comes as quite a shock.

You must not destroy the two ships with the ability to shift objects from the main universe.

Picard comes to believe they plan to invade the 'main' universe, simply because they have no other choice.

However, in September 2011, DC comics rebooted the main universe.

A bubble perpendicular to the main universe, not intruding into it?

He is a mutant supervillain in Marvel Comics' main shared universe.

Predator X is a comic book character, in Marvel Comics' main shared universe.

"Artifacts", he explains, are from parallel universes that have accidentally made contact with our main universe.

The Beyonders are a race from outside the main physical universe.

It exists within Marvel's main shared universe.