Mutant Dandelions............................................ or Polyploidy?

So in May, I was walking across the yard, trying to get away from all that writing I needed to do to finish the semester.  I looked down and this is what I saw.

I flipped it around looked at it some more because I wasn't sure if I was seeing it correctly or if my brain was so tired it just thought it saw a ginormous dandelion head in the yard.

Yup, ginormous dandelion head in the yard, confirmed! So, I ran inside and grabbed my camera and took some pictures before I thought to myself (how am I going to show just how big this thing is) and then promptly ran back inside to find a standard house key for comparison.  You all have a house key right? Look below and check this ginormous dandelion head out.

I looked around the yard but I didn't see anymore mutant dandelions just this single one.  So what would cause this kind of mutation? I looked on the Internet but couldn't find any good information on why or how dandelions mutate.  However, I did find several blogs with pictures of similar mutations so I added their links below. If you are interested in specific dandelion information then please click away.

Dandelion Mutation Pictures on Blogs:
Big stem, tiny heads from Garden Thyme with the Creative Gardener
Big stem, tiny heads + possible mutation explanation from Nuttin'
Big stem, tiny heads + my favorite mutation explanation (polyploidy)  from TYWKIWDBI ("tai-Wiki-Widbee")

Polyploidy is any change in the number of chromosomes in an organism.