If one were inclined to Science Fiction writing you could hide a nice big base and invasion fleet in that thing. Our solar system, a speck smaller than an atom in comparison with the observable universe, is an endlessly fascinating place. Of course, in the opposite direction so is the bottom of your average garden pond.
I was thinking along those same lines. Every one of those holes could be made into a separate ecosystem if you cover them over with a film of some sort to protect the artificial environments inside. Unless of course it really is made of some kind of spongelike material.
If an invasion, it’s been danged slow getting here. Of course, that’s just my Earthcentered thinking there, maybe they have no interest in us.