I have a theory of my own. Granted, there's no proof or evidence and I'm probably just pulling it out of my arse, but it's good fanfic bait. Plus, it's what I'm using for Sea of Dreams.
*ahem*
Lavos did not come from another planet. It has traveled through space, yes. But, to the surprise of all who would learn it, Lavos was created... on this planet.
Say a tribe of precursors dating back even farther than prehistoric times. Shit happens, either their creation goes out of control or they destroy themselves, and Lavos is left wandering the cosmos. Feeding. Evolving. Surviving.
Then, eons and eons later, come 65,000,000 BC...
Lavos wasn't invading from a far off world. It was coming home! For what purpose, none can say.
How's
that for irony?
Puts a whole new perspective on the series as a whole, wouldn't it?
It's something to ponder, anyway.