kay so in this headcanon, the changelings' black, love-devouring form was never meant to last them to adulthood. Queen Chrysalis has stayed in the juvenile stage long past its expiration date, and as such, her body has begun to petrify and crumble from the extremities inward. However, the stone that her limbs have become has similar properties to her old throne, i.e. it absorbs all non-changeling magic. Through meditation and force of will, she's even managed to grow a funnel-like protrusion of the stuff out the top of her head, so that she can suck up foreign magic and channel it easily back out of her horn. She's known for years that staying like this will eventually kill her, but in the meantime it gives her a crucial advantage over the unicorns of Equestria — one that the rest of her hive was beginning to develop as well, which is why she was so eager to keep them in the dark about their true potential.
Is her 'mane' supposed to be made of fins or membranes or something? It's got holes in it. In the show. And, like, hair doesn't really work that way, so I'm just wondering.