All great art must have at least one mistake lest it be perfect and bring about the wrath of the gods.
I think it's a cookie. A very large cookie, given the "21 milles (33 km)" notation, but a cookie nonetheless.
It would certainly be grist to the pious and one in the eye for science if it turns out to be god's own cookie... Mind you, there would have to be a pretty large cup of tea floating around in the void somewhere!
That's very pretty. But if you don't like the streaky effect (I do!) you can reglaze and refire it, can't you? It's been a long time since I did ceramics (in high school) but I do seem to remember things can be fired several times. Sometimes ceramicists do this on purpose, to put effects on top of effects.
I am happy that the local birds have taken to my improvised feeding station in the back garden. So far, I have had Blue Tits, Coal Tits, Goldfinch, Robins, Great Tits.
Tell me where your back garden is! I'll relay the info to some of my cousins and you'll have a bunch of interesting new visitors! (We like walnuts, BTW, preferably still in the shell...)