the main reason grace and rocky are sooooooooooo everything to me and to each other is because like, are they soulmates? yes. are they best friends? of course. are they doing nerd telepathy? absolutely. BUT WAIT THERE'S MORE!!! imagine for a moment that you could never again consult a human being on anything, ever. anything that happens to you medically mentally emotionally etc you have to figure out for yourself. you have textbooks and resources you can consult but if you're delirious with pain or fever or panic you cannot reach out to anyone who knows what it is like to be a human who can help you. no one can ever tell you yes i have experienced that too. the closest thing grace has to another human being is his rock spider best friend, and he taught rocky everything he knows about being human. how terrifying must that be!! how exhausting and isolating!! and how utterly moved and relieved and floored must grace be each and every time rocky observes something about the human animal that grace didn't teach him, or deliberately learns something from mary, or picks up some mannerism unconsciously despite grace not intending to pass it along. like, i am the only human on this whole planet, there is no one here with whom i have shared bodily or emotional experience, but that's okay because you loved me enough that you became half-human too. so i wouldn't be alone. so i would have help. rocky is all of earth for grace and he became that willingly and he doesn't regret it for a second. that's a level of devotion and care and codependency you just don't see every day
