What does this cat's tail mean?

Question

I was walking near a park around the neighborhood and encountered a cat. It approached me, meowed, laid on the ground and stretched in front of me and I continued walking without petting it.

However I was curious about its tail- as it walks, its tail lines up against its back (pictured in my masterpiece below)
When it laid on the ground its tail did move around but once it got back up its tail went back to "sticking" against its back:

Why is the cat's tail doing that? I found a helpful diagram on Google but I didn't find what I was looking for.

Answer 1

That is not a normal tail position for a cat. In fact, I don't think cats normally can lay their tails on their back like that.

I suspect the cat you saw may just have a kink in its tail that is causing the strange position. This can happen from normal genetic variation, or from a break in the tail not healing correctly.

Answer 2

I was able to dig up some more information. The cat I encountered may have been an "American ringtail cat". Like Kai has mentioned in the other answer, the tail bend may be caused by a genetic variation or mutation.

The American Ringtail Cat (also known as the Ringtail Sing-a-Ling) is a fairly new experimental breed that started with a rescued cat named Solomon in 1998. When Susan Manley found him, he was a 2-day-old kitten who needed to be bottle-fed in order to survive. As he grew and reached the age of 4 weeks, she noticed that he had a unique tail that would curl over his back.
After having Solomon examined by a veterinarian, it was determined that there was no underlying medical issue or deformity that caused his tail to curl. The cat seemed perfectly comfortable and content, holding his tail curled over his back when relaxed.

And this chart outlines the Ringtail tail range in the blue box below:

Sources:
https://www.petguide.com/breeds/cat/american-ringtail-cat/
http://messybeast.com/curly-tailed.htm