I was drunk and being a bit facetious. The general scientific consensus points to random mutations and natural selection. But how do mutations end up producing functional and adapted limbs? And why do decapods evolve to crabs? The mysteries of DNA. It's one of those concepts, like the birth of the Universe, self-consciousness, that we will never have a full understanding of. In the case of dogs(and foxes) domestication does change their appearance like the coloration of their coats and floppy ears but there's also cross-breeding at play. Still a mystery to me why those changes occur.