At some point, Grace of course realizes it's living in a zoo enclosure. Then comes a Discussion. 

"Rocky."

Rocky is totally panicking - it told the xeno team to not let Grace know! Now Grace is going to be offended or mad about being a zoo animal! There's no way to sugarcoat this! - and screeching out apologies. It won't be able to withstand Grace being mad at it, because the last time Grace was mad at Rocky Grace ignored Rocky. IGNORED. The silent treatment had grated so bad on Rocky's nerves it felt like it was going to go insane.

"ROCKY! CHILL OUT!"

Rocky slows. Grace is still kneeling from where it had settled after first saying 'we need to talk' (worst words in the universe, by the way). Rocky doesn't get any closer, just fiddles nervously with its fingers.

"Rocky, look. This isn't- I'm not mad about it. Honest! I kinda…" It rubs the back of its 'neck' with a hand. "Kinda already figured it out a while ago."

Grace laughs, flashing its 'teeth'. "I mean, we'd do the same thing on Earth if this was all reversed. I get it! I'm an alien, I knew this was a possibility."

"Along with dissection," Rocky grumbles. "And starving to death. Does not mean good thing. Does not mean Grace happy about it."

"But I am! Look, Eridians are learning from me, right?"

Rocky hums a begrudging confirmation. 

"Then I'm happy about it! You know me. Once a teacher, always a teacher. Plus, it could be worse."

That is true, all of it. Rocky sighs. "Okay. If Grace is sure Grace not mad at Rocky…"

"I'm sure, buddy. C'mere." Grace reaches forward and wraps Rocky in a 'hug'. Rocky accepts it, reciprocates, feeling the familiar noises of Grace's organs. 

"Team will ask more questions," Rocky warns. "Want to do experiments on human behavior."

"Oho, boy. I'm looking forward to that."

And Grace isn't lying, and neither is Rocky: within days of the conversation, the xeno team is approaching Grace and asking many more questions about human biology, about enrichment. They already were, of course, but something seems to have emboldened them. 

What everyone finds most ridiculous is human evolution, though.

"Sorry," Historian Lilith wheezes out. It's almost laughing too hard to keep going. "You're saying- you- humans just walk your prey to death? And you became the apex predators on your planet? How does that work?!"

Every other member of the team present is cackling, including Rocky: Grace alone stands sober, pouting in the way it does when it's offended. 

"What's so unbelievable about that?! It's a very effective way to hunt!"

Rocky snorts. "Grace lying. No way walking is efficient! Ambush is better. Example!" And Rocky lunges for Grace, relishing the squeal and the scramble backwards. Then Grace stands up taller. "Okay! I'll show you. Who wants to get hunted?"

Everyone instantly steps back, leaving Rocky at the forefront. Figures. All that talk about how it's not realistic and yet they scatter at the idea of being the prey. Frankly, Rocky can't blame them - nobody wants to be hunted, after all, especially by an alien that breathes oxygen - but it raises a hand anyways. "I volunteer. Grace hunt me. Then we know truth once and for all."

The grin that split Grace's face somehow seems even creepier than usual. It goes off to prepare, murmuring about contacting the substitute teacher that takes over when Grace gets sick. Huh?

Rocky disregards that and prepares by simply making sure the atmosphere suit is fully ready. It knows Grace isn't really going to hurt it, but it has to reassure several members of the xeno team and Adrian, who's come to watch, of that fact. "Seriously? It's Grace. Grace won't hurt me. Grace can't even hurt me!" It starts to mutter about how ridiculous they're all being when someone points out that Grace could potentially break the atmosphere suit with the abundance of rocks in the enclosure, trapping Rocky in the deadly Solean-safe atmosphere, which stops Rocky dead.

It's Atmosphere Specialist Superman, well-known to be paranoid even at the best of times. Eridians have no 'faces' like Soleans, but Rocky deliberately rotates towards the idiot just to hammer in the absolute stupidity of what Superman just said, and then smacks Superman so hard several team members have to pull it off of the scientist. It's swearing and screeching the entire time, and it takes a few Earth hours to calm down properly. 

The very idea of Grace deliberately hurting Rocky in such a way - when Rocky knows for a fact the scars from the Adrian Incident are still fully apparent to the Solean senses, when Grace spent months freaking out over every little sneeze or cough Rocky made when in the prototypes of the atmosphere suit - is preposterous. Grace would never ever hurt Rocky like that, would never do anything to expose Rocky to its atmosphere ever again even accidentally. They're both so very careful about it. Rocky is still steaming about Superman's insinuations when it walks inside Grace's enclosure.

Grace is waiting by the airlock. Rocky huffs. "Unfair. Go farther. Too close for start, cheater." 

Grace holds up its hands in the almost-happy movement ("When I put my hands up like this, this means surrender.") and steps away a good distance. It's still smiling. "Not gonna matter, Rock," it calls. "I'm about to get you back for alllll those times you ambushed me on the trip here."

"Yeah, right!" Rocky shifts, preparing to run. "We see who is better predator."

"Ready?"

"Ready!"

"GO!"

Rocky bolts. The sand is hard to traverse, its arms slipping both from the xenonite covering and the loose grains, but it already knows it's a faster runner than Grace. And when it clicks to see where Grace is, Grace is so far behind it's laughable. Oh, this is gonna be easy. 

Rocky reaches the edge of the biodome, a little worn out. Luckily, it just had a sleep cycle, so it won't need to sleep for another few Solean days. Grace is out of range. HA!

It meanders back closer until it can hear Grace, leisurely strolling along the beach. "What wrong, Grace? Too slow?" It calls out. 

A ripple of laughter comes from Grace. "You'll be eating your words soon enough." It sticks its hands in its pockets. 

Rocky snorts, and decides to continue to be a little shit. It goes back and darts around Grace, mocking it, staying juust far enough away where if Grace lunges Grace won't even be able to touch it. Grace does give chase eventually, but Rocky just carefully climbs up the cliff face. Damn, humans are stupid! Every time Rocky thinks they're not so bad, Grace does something like this. It's not even chasing Rocky! It's just slowly following. 

The biodome cycles over to night, Rocky can tell by the click! of the flashlight Grace carries. It settles on top of the cliff, enjoying the sounds of Grace trying its damndest to climb the cliff. Technically it's well past the time Grace should be asleep, but they're both too stubborn to call quits and the xeno team isn't in a hurry to interrupt this glimpse into human evolution.

Rocky has to run again when Grace reaches the top of the cliff and starts to chase it again. This keeps going, Rocky running and mocking Grace, Grace just continuing on, unshakable. Rocky only starts to worry when night falls again and Grace is still able to catch up to it!

It yells to Grace, who's some distance behind. "Grace need sleep."

"Grace has slept." Grace shouts back. "Remember, I can wake up easily. I've been sleeping and eating regularly, I promise."

"Good!" Rocky lets itself feel some relief that Grace isn't neglecting its health for this experiment. Then it goes right back to insults. "Then Grace have no excuse to be so slow!" It makes a 'fart' noise in Grace's direction and scuttles off, laughing at the offended sound Grace makes. 

Day comes again, and Rocky gets frustrated. What in the actual fuck?! Something's not right. Grace has been at this for two Earth days and nights now. If Grace was going to catch Rocky, shouldn't that have happened by now? Is Grace even taking this experiment seriously?

Well, Rocky does know Grace is taking it seriously, because Grace is doing it. Hasn't given up. Hasn't called it quits. So the only reason why the experiment is still going must be because this persistence way of hunting is, in fact, not effective, and Grace is just too stubborn to admit it! HA! Get wrecked, Grace.

Frustration turns to glee, which then curdles into nervousness as the day still goes on with no sign of Grace stopping the pursuit. They've both been running in circles: the biodome's not that big, all told, and Rocky can't access a quarter of it due to the fake ocean. And Rocky can feel a sleep cycle is imminent. It's exhausted. All the running it's been doing must have brought the sleep cycle on sooner. And Grace, last Rocky heard, still shows no sign of tiredness. Shit!

Rocky pushes itself just a little harder, until Grace is far beyond Rocky's range of hearing and Rocky is well hidden: Grace is still on top of the cliffs by the wall of the dome, while Rocky's down below nearer to the water. Then it finds a cave. It knows this cave in particular has a room beside it where the xeno team has been watching on the camera feeds and listening to this whole debacle. 

"Must sleep," Rocky manages. "Can't keep going." It collapses, and the world vanishes. No worries. Grace won't catch up, and if it does, it won't think to look for Rocky here.

When Rocky wakes, it first hears a clamoring from the observation room. Many voices shouting over one another. It sends a spike of fear through Rocky, and it taps at the floor to hear better - and nearly has a cardiac failure then and there, screaming louder than it's ever screamed before in its life.

Grace is standing right. over. Rocky. Looming, really, and it's never sounded taller or more ominous.

"Hiiii."

Then Grace plunges down, wraps its arms around Rocky. "Gotcha!" It opens its mouth and presses it to Rocky's carapace, leaking all over it and pressing its tongue to the xenonite as if it's trying to eat Rocky.

Rocky shudders in disgust and cusses Grace out with every word it knows, smacking it lightly with an arm. "CREEPY! Scared Rocky, nearly kill Rocky with attacking heart! No no no bad Grace! BAD BAD BAD GRACE!"

Grace is laughing, sending vibrations through Rocky's body. "I told you," it says in that light singing kind of voice it likes to do. "I tooooold youuuu! Persistence predators, baby!"

"That no count! You wait until I fall… asleep…" A horrible idea begins to dawn on Rocky. "No." There's no way. There's no way. It's too awful to think of, and yet it's the only possibility.

"Well-" Grace settles back, crosses its legs underneath it and turns towards the window to the observation room: where, by the way, everyone's gone silent with their own realizations. "You guys didn't let me finish explaining earlier. See, a lot of prey animals on Earth are very fast, like Rocky here." It gives Rocky a noogie. "So humans evolved to be able to endure long stretches of exercise like this. We chase an animal, track it using its footprints or the direction it was going in usually, and then eventually the animal's so exhausted that it has to sleep, and that's when we attack and kill it for our food. So that's what I just did!" Grace flashes its teeth again. It's terrifyingly happy about all of this.

Meanwhile, Rocky quite literally cannot move from fear. Grace has sparked fear before: their first meeting, when Rocky had no clue what to expect but it certainly wasn't some squishy cold bag of meat that breathed oxygen of all things; over Adrian the planet, when the ship had been sent into an uncontrolled spin and Rocky had known what it would have to do to save Grace and Earth and Erid all at once even if it meant death; for a few moments when Rocky had been floating in its tomb, the original Eridian ship, and heard a cracking thumping sort of noise coming from space, right before it'd discovered that the noise was Grace coming to save it.

All of those instances were tiny bits of dust next to this type of fear. The revelation that Rocky's wonderful and clumsy friend could have, just now, very easily killed Rocky in Rocky's sleep and that its species did so regularly was the singular most horrifying concept anyone could ever have imagined. Grace probably had no idea that the Solean way of hunting was the stuff of the worst Eridian horror stories. Something that just kept going, kept chasing you until you were forced to sleep? Fucking WHY?! WHY did Rocky have to meet AND BRING HOME the ONE species it knew of that DID THAT?! WHY?!

"That-" it weakly starts - still feeling like it was about to, as the Soleans say, 'shit its pants' - "Very… nice, Grace. Thank for demonstration."

It crawls out from under Grace's arm. "Back soon," and lunges for the airlock. It needs… more than a little bit of processing time. That whole thing was fucking disturbing.