Have we done

[zeitghost]

the brain in the ovary?

And if not, why not?

https://www.newscientist.com/article...d-girls-ovary/

Lovely.

Talk about being in two minds.

[Uncle Albert]

A brain in the ovary eh? What a clever ****.

[ladymuck]

Gotta love a vestigial twin. They're quite common.

[ladymuck]

Sounds more like a teratoma, but you may be correct.

It is a teratoma; I just like vestigial twins better. The former is exactly what was described whereas the latter is pretty much a fully formed "body" that is parasitically living off the host (they would have been siblings if something hadn't gone wonky).