"I AM FRIGHTENINGLY POWERFUL. SPEAK TO ME."
Cam makes little transponder cameras and plants more mics in ships with them. All the ships he can find.
He repeats himself.
Well, he's tracking them as they go. "...Do you happen to know where they go when they're not here?"
Some of the fleeing ships are shot down by their panicking allies, but not all.
"We won't be able to follow you, but you don't seem to have needed us so far... how long should we wait before trying to dismiss and resummon you?"
Cam hands him a thing. "This will eventually - depending on weird physics - have a delay of several minutes, depending on how far I chase 'em. But you can talk to it and it'll talk to me. Like so," he says to his computer, and his voice echoes out of the thing. "If I don't answer and there's not an obvious reason and the delay hasn't crept up high enough to explain it and I didn't tell you I'd be out of touch, then you unsummon and resummon."
And Cam flaps for some distance and makes a high-speed atmosphere-friendly shuttle around himself and zooms away, chasing after scared evil aliens.
Eventually, though - after many, many planet-lengths, a distance that approaches the legitimately astronomical - it becomes clear that there is an edge to this universe. And hovering in midair, very close to that edge, there is a portal no bigger than an ordinary doorframe.
The aliens stationed at the portal are frantically shooting down all their own ships that make it this far, flashing emphatic lights to warn them away.
"Hey, did you know that the universe has an edge. With a fucking door in it. WHY IS YOUR WORLD THIS WAY."
Cam takes a picture and sends it. "It looks like an EDGE! With a DOOR in it! Why!"
Then: "...It looks like the edge of a Sphere. A very large Sphere, to be sure... but that's certainly a portal."
"It's... not impossible, I suppose. But I can't imagine how old this person must have been when they died, for their Sphere to be this enormous."
"Well, your universe has a door and that's how the evil aliens are getting in. Any guesses what I'll find if I rush it?"
"Another Sphere and portals to more, I expect. And more of the Enemy. Until you track them all the way back to where they came from, wherever that is."
"If the owners of both connected Spheres are dead, the portal is permanent. The owner of this Sphere must be dead, or we'd all need their permission to create portals out of it; I find it hard to imagine that the owner of the connecting Sphere might be alive, given that their Sphere has presumably been totally overrun by the Enemy."
"Well, that's inconvenient, I guess I have to follow them home. If you would like to check the inter-sphere-ability of these communication devices by stepping briefly into your own Sphere that would probably help, although my bet is that they don't work between spheres."