Out of Nowhere

I am ready to start sharing my garden again. Now, I know that everyone has seen a daffodil. But this one is special. It came from nowhere in the middle of the bed of iris that I planted from my own cross-breeding seeds. It is not one that I planted, recently or in the distant past because I do not like these double flowered types and would never have planted them. I have a few possible explanations:

• It grew spontaneously. This may be true, but it I, unlike some presidents, believe in science - daffodils don't just appear out of nowhere.
  
• I planted it in the past when it accidentally got mixed in a batch of other types at the store. It then grew legs and walked down the hill and planted itself in this location.
  
• Some of my other daffodils had a night of passion one year, and this is the result.
  
• It was there for a time and this year got large enough to bloom. Yes, I believe there were daffodil leaves there in the middle of the iris iris bed last year with no blooms.
  
• Someone or some animal known to dig up bulbs did so from a neighbor's yard and planted it here years ago, and it got enough food stored up this year and bloomed.

I have lived here for 31 years, and never saw this daffodil on the property. There is one more bloom in the same "clump". I checked the immediate neighborhood -- no one had this type of daffodil.

Offer your own explanations.