It's not a mystery any longer. It's simply a yellow squash. For some reason, I thought it might be one of the wild species that grow native here in Colorado. At least, it could have been something exotic, not just a garden variety summer squash. Even so, how did it get there? It is not the same cultivar as what I have planted for the past two years. My best guess is that it was a seed that was dropped by a squirrel.
