SubTerra Verse?

[Lubbock]

I know this is unlikely to actually become a thing, but after imaging Doomsday (DC Comics) pummelling someone to the centre of the Omniverse... I wondered what was actually that far under the Omniverse? Of course we'd find caverns and mineshafts and Omnillium springs... but what's past all that?

That's when Dean/Kylo said 'more verse' and I thought 'What if there is an underground verse accessible from every main verse except the Nexus, just by going far enough underground?', and so spawned the idea of SubTerra. I'd love some input on this idea!