Sophia_Forever!

2. Grace eats Taumoeba but who said it will stop evolving just because Grace thought it should?

3. Taumoeba evolves in Grace’s body, binding itself to his DNA as so many things have done before during our own evolution.

4. Grace becomes capable of consuming Astrophage (the most energy efficient organism in the known universe).

5. Grace’s organism becomes more energy efficient as well and therefore its internal structure ages a lot slower.

May I present the best apple:

He understands.

They arrive to Erid, and one of the first things Grace does is playing for Adrian a little speech he made in Eridian using his recordings of Rocky's voice. And it's just... instructions. Mostly.

"He has a lot of anxiety about people's health and will probably freak out about yours at some point, don't dismiss it and let him see that you are okay."

"He is terrified of being alone, please make sure someone is physically close to him at all times."

"He is scared of falling asleep and will delay it as long as he can, you need to pay attention to his sleep cycle or he'll be hurting himself."

"He downplays everything bad that is happening to him, mental and physical, please keep an eye on him or he'll be ignoring his health completely."

"He never gave up, but I might die very soon and I'm not sure how he will react to it. Please be with him, even when it's not easy. He loves you. He wanted to return to you so badly. Even though he probably has changed, this is still him. Please keep loving him. He needs it more than ever. He'll need it when I am gone."

...Adrian is very annoyed because a) the fuck do you mean by implying that I'll leave him, b) the fuck do you mean by implying you know him better than I do (Adrian does have to begrudgingly accept this one later: Grace is objectively more familiar with Rocky's trauma responses), and c) the fuck do you mean you're gonna die no one's letting you die shut up and get into the lab we have science to do. They become friends fast, bonding over worrying about Rocky together.

But for a few years (cough, decades, cough), a baby pebble is about as hard as a soft-shelled turtle—or a normal turtle, if they're a bit older. Disadvantages aside, there is an advantage to being able to see your offspring's internal functions. And until their vocal bladders form and they're capable of making multiple complex sounds, being able to see what is hurting is absolutely helpful.

It's a universal experience among parents to lament the day they can no longer hear their pebbles' heartbeats.

That is to say, Rocky knows Grace is an adult, okay? He isn't someone who anthropomorphizes, and he isn't going to start now. Statement.

But when he first heard Grace in all his squishy glory— heart pumping away, lungs filling and deflating, organs digesting food— his brain went full baby-fever mode. Frankly, he was white-knuckling the urge to find the nearest hypothetical cave, bundle him up into a proper nest, and wait for his skin to absorb the surrounding minerals and start hardening properly.

But because Rocky is sensible and proper and not going to infantilize his best friend (he swears to God, stupid fucking instincts, shut the fuck up!!), he won't.

But sometimes the urge to squish his best friend is overwhelming. He just pinches at him through the permeable mesh of his ball. And Grace will screw up his face (so soft) and go what’s up bud? I piss you off or something? (He learns what bruises are and sulks for half a day afterward.)

All of that aside, once again, Rocky has gotten used to Grace's heartbeat, his clumsiness, and his one-tone voice. That's his best friend, and he's smart and just as capable as any other adult. He is also the cutest fucking thing to Eridian hearing. Is he also disconcertingly alien, definitely— His size, the limbs, the head protrusion (and other protrusions), the leakiness detracted maybe. But his cluster-sibling once cooed at and brought home a pet sulphur slug because, oh my spirits, hear his squishy respiratory system and you tell me that's not the cutest thing on the planet! It blurbles, Rocky! It fucking blurbles!

So, as Erid draws closer and Rocky/Grace become more excited and stressed. (The food has yet to run out, and as good as Erid is, they need substantial help from the human side to figure out how to make proper human nutrition. And finding the right informational packs in all of human knowledge is a very big undertaking.)

Because while Eridians are incredibly strong and tough on the outside, on the inside they are actually quite fragile:

They have no immune system, so anything that makes it past their enclosed carapace and internal heating will pretty much kill them

They have no natural defenses to radiation of any kind

In general they have very little organic matter so anything that targets their cells directly is quickly lethal

They are partially cold-blooded and live at a very narrow temperature range (about 20 degrees C)

They rely almost entirely on one, highly developed sense and are helpless if deafened (can't even remember the layout of a room)

They are completely helpless while asleep and can't control when that happens

They will forcibly become dormant after eating AND when badly hurt enough (their equivalent of going into shock)

They require more energy to function than humans do, and have very little organic matter to burn in the case of starvation

In contrast, humans:

Have an aggressive immune system and internal mechanisms for dealing with cell damage

Have adrenaline which allows them to temporarily ignore injuries and perform abnormal feats of strength

Are persistence hunters built for economy of movement and capable of extreme levels of endurance

Exist in a very wide range of habitats and on a diverse diet

Are very hardy in general, able to survive massive injuries, lack of sleep, prolonged starvation, and intense environmental conditions if given proper care

The quintessential example of this dichotomy between strength and endurance is the Going Fishing incident in the book: Rocky is able to survive and move in G forces that are killing Grace and to physically wrestle off the chair crushing him, but he collapses from his injuries almost immediately after. Despite being injured himself Grace then carries his 400lb friend up a ladder, is badly burned returning him to his atmosphere, and then proceeds to get some basic medical care, hype himself up on pain meds and keep working (albeit rather badly, lol) while Rocky forcibly sleeps.

Equiping an armor tutorial

The actual director is Natted JWHJ0715, and they deserve credit!!!