I have a stupid time travel au idea! (This is technically part of a greater time loop fic I've been thinking of but it doesn't matter)
Grace is back on Earth a couple of years before hes Strattnapped but Rocky is also here! (No he doesn't need the suit dont question it) and since they dont want Rocky to contently have to stay in Grace's place, they use both of their incredible smarts to come up with a plan!
So Grace goes and gets diagnosed with PTSD and then gets Rocky certified as his Service dog! Since Rocky does genuinely help and Grace helps Rocky with his ptsd its a perfect plan!
Except they some how only managed to use 2 brain cells each as I making this plan they fail to relise Rocky really doesn't look like a dog, maybe if you squint reeeeeal hard, but their not fooling anyone.
However they get away with it somehow, when people ask Grace what breed Rocky is Grace just responds with "He's a stary :)" and they kinda stop there.
Now picture, Eva Stratt, showing up to Grace's classroom, this guy has been recommended by basically everyone in the speculative Astrobiology feild, she's read his file, she knows he has ptsd from an unspecified event and a service dog, so she believes she knows what to expect then she actually enters the classroom.
Grace is at the front at his desk, and sitting at one of the kids desk is a rock crab spider thing? And its just
Startt: The fuck is that?
Stratt: why does it sound like that?
Rocky does end up on the Vat, cause while Stratt doubts that thing is actually a dog he does appear to be helping Grace and she's not gonna take someone's service Rock crab spider away, even if said guy keeps insiting that its a dog.
Nobody believes Rocky is a dog, not only because of the obvious, but also because Grace would stop by to see what the engineers are up to, stop as Rocky says something then tell them what he said, The engineers are like "Umm isn't he a dog? How does he know this?" And Grace just responds with "He's very smart :)"
The Vat has theories on what Rocky is ranging from a genuinely kinda fucked up dog to weirdly advanced robot to Alien, Grace is unaware about this, Rocky is very aware and using it to fuck with people, like the little shit he is.
The only two who get confirmation on what Rocky is are Yao and Ilyukhina, who stay alive! Cause Rocky was there to watch them sleep, so they get to Tau Ceti and they find the Blip-A and finally confirm that Rocky is an alien (and both him and Grace are time travellers????)