What is it? And what can you do with it? It's a sock. One of a pair.
I kind of like these socks. They remind me of the Cat in the Hat. You know the story. The one in the book we didn't have to read. At my house it came in the mail along with The Cat in the Hat Comes Back and with One Fish, Two Fish, Red Fish, Blue Fish. About 45 years, or more, ago. Whew! That sure dates me! And I still like the Cat in the Hat.
These sock were actually made for Laura. When she put them on we decided they were too short. They also needed a heel. I thought I could get out of making heels by knitting up a tube but it looks too strange.
So, what's being added is an "after-thought heel". Great name, so creative, but yes, that is actually the name E. Zimmerman gave it. If you knit, her books are some of the ones you ought to have in your library. She has a lot of great suggestions. Even though her books were written years ago and the models are all out dated the techniques still apply.
So these socks, much like the Cat in the Hat, came back for another round (Pun unintended. Just the second one.)