It happened again!

This is really strange. I've been growing squash for a good while and I've never had a double one. And this year, I get two! What kind of portent is this? Livy would have a blast. Maybe Hannibal is invading Rome again! Or some other disaster of equal weight...call the diviners! Call the priests!

But seriously now, should I save the seeds from this plant? Do you think it's a mutation that would be passed on? Or is it just a chance happening that isn't in the seed genetically?