>>55060434The second level of the multiverse is based on the theory that the Big Bang wasn't the actual beginning of everything. This theory proposes that "outside" the regular space, there's another dimension that is expanding incredibly fast, several orders of magnitude faster than our own universe. Our universe is like a "bubble" that appeared in this larger universe.
The theory proposes that this larger universe could house several of these "bubbles", appearing several times across space. Each time a bubble universe appears, it has a completely different set of laws of physics. Unlike the Level 1 universe, where everything had the same beginning and the same physical laws.
In pokémon, this level is represented by the dimensions where Dialga, Palkia, Giratina and Arceus (and possibly the Unown) live, such as the Distortion World. All of which are universes with different laws of physics.
The representation of this multiverse as "bubbles" even appears in the Arceus movie, as the time-space axis (pic related).