Upon further observation and research, it seems this is an Annual Sowthistle, not a mutant dandelion. Darn.
This time of the year that we actually have some growth in our back yard. The rainy season. It's pretty brown the rest of the time because not only am I lazy, but I don't feel like wasting the water it would need to flourish. What ends up growing is just a little bit of grass and lots of weeds like clover and dandelions. The guinea pigs don't complain as they love clover and dandelion leaves.
So now that we've we've had some rain, a good portion of the back yard is fairly green. Yes, it is still mostly weeds, but it looks pretty. The dandelions have gone NUTS and are taking over!
What really caught my attention and inspired me to grab the camera was what I will henceforth call The Biggest Dandelion Ever. I spotted what looked like a baby tree pushing up through the ground. I looked closer and recognized the yellow flower blooming on top and the distinctive leaves. The thickness of the stalk and height of the plant was impressive, so in order to get some perspective, I made Rusty sit by it. He has a good sit-stay, but was nonplussed and kind of annoyed.