This just came to me when I was falling to sleep so it may be confusing, but I had to type it to see if it worked... It's a little crazy and takes place during "Fragile Balance". It uses Little Jack as the Jack in question. Response to the "Bad Dream Jack?" challenge on Stargatefan.
Little Jack finds himself battling another odd race bent on galactic domination along side three other kids, a falcon, and an alien, battling a race of parasites known as the ...Yeerks.
After an exhausting day of trying to convince the rest of the SGC that he was really Colonel O'Neill and reading some old "Animorph" books someone had laying around the mountain, "Little Jack" slumps down to sleep in the armchair of his room.
Not two minutes later, Jack hears a voice calling him. Jake! We need you here now! the voice called out in his head, while he was trying to figure out why it sounded so odd, Jack sat up. He was wearing his clothes that he had fallen asleep in, nothing odd, but under the clothes he was wearing a tight fitting suit and his clothes fit now, but Jack had no time to think about it because at that moment a falcon swooped in the open window and looked at him oddly. Jake, do you want to hurry here, Erek's got vital information! Come on! You can do the hawk, just hurry!
Jack looked at the bird and had a name come to his head, he thought it was the name of the bird so he attempted to answer the bird Just a minute, Tobias, just a minute and he was gratified when the bird responded with a swift "Okay" and flew out the window. Jack wondered what Tobias had meant by "do the hawk" and why Tobias sounded so much like Jonas (Ughh, Jonas!), but Jack thought about this cryptic message and felt like needles were being poked through his skin. Soon there was a hawk standing where Jack had been and in his shock, Jack the Hawk flew out the window. Jack flew to a barn where he heard the voice he had I. D. ed as Tobias, and flew inside.
Inside the barn there were several people who looked familiar but different were talking to someone who looked familiar (That's Lt. Hammond! Jack thought to himself, recalling the young man they had met in 1969). Suddenly Jack realized why the people looked so familiar to him; there was a young Daniel, a young Sam, a young Janet, and a boyish Teal'c in this group. But Jack Landed and became himself again. "Jake, Erek's found a new way into the Yeerk pool, we're gonna go in," the Mini-Carter said, being agreed with by the Mini-Teal'c, "Cassie's right, Prince Jake. We need to infiltrate the Yeerk Pool," as the Mini-Teal'c spoke, the idea suddenly became clear to Jack, they were using Code-names... (I got it!)
Now Jack tried to remember the names of the others, and partially succeeded. "Of course we are... Ax, we need to keep the people of Earth safe!" He said to the Mini-Teal'c.
"One problem," the Mini-Daniel said, "Renée's been taken and is now a controller, we've got to save her"
"Marco, you know we'll do anything to save one of our own, but Renée's not an Animorph," the Mini-Janet said. By this point Jack realized that they were NOT using Code names, but that these people were who they said they were.
"Also," the Mini-Hammond... Erek said, "A small fighter craft of some type crashed at these coordinates," a hologram of a place near by was shown to the group.
"We'll check that out first," Jack said, recognizing a Death Glider, "If there are more of those worms we should keep them from the Pool, starve 'em out, ya know"
Out where the Death Glider had crashed, Jack and the Animorphs looked around. Jack found Apophis in the wreckage. Marco saw Apophis at the same time. "It's the Visser One!" Marco ran off towards the others and at that moment Apophis, or the Visser One, reached up and forced Jack's ear to be level with his and the Yeerk crawled out of the body of its host and went into Jack, straight through the ear canal. Jack felt his control over his body slipping away and saw the Visser One "decided" to "infiltrate" the Yeerk Pool. Jack saw the Visser One make plans and thought to himself, because that was all he had control over now, This is worse than being snaked! I've been WORMED! SLUGGED! I'm a WORM HEAD! Jack saw the Visser One lead the journey and then he found himself with his head in a pool of sludge. The Visser One crawled out of Jack's head like Machello's "Goa'uld Killing Bugs" had, sliming its way out of his ear.
Jack was in a cage, he had been forced in by a walking Razor Blade and he did not want to mess with an eight-foot tall walking razor blade.
Jack was taken out of the cage and one of the Walking Razor Blade creatures forced his head into the pool of sludge. Jack did his best to fight; he started to yell out when his head was shoved under.
"Sir! Colonel O'Neill! Wake up! Sir, you're asleep!" Carter was standing over him.
"Where am I?" Little Jack asked.
"You're at the SGC, It's Okay."
At that moment Daniel walked in. "I heard you yelling in my office, Jack"
"Sorry," O'Neill said
"Hmmm. Bad dream Jack?" Daniel asked.
"Yeah," Jack stuck his hand into his pocket and found a tail feather of a falcon, "Or not," Jack muttered as the other two left the room.
Hope you enjoyed reading this story as much as I enjoyed typing it