Equestria meets R.J. Macready

MacReady turned to the Girls and Spike and pulled out his pistol and shouted with distrust

"Get on the fucking ground, you parasitic motherfucker!"

The 8 were left shocked at MacReady and decided that they should try and calm him down.

Rarity, with a look of offense said 'Parasite?!, excuse me sir, but we are ponies!"

MacReady angrily said "DO IT!!"

The 8 decided to obey to not escalate any more hate from R.J. and quickly got on the ground and MacReady took out a blood test machine and put it on each of them, taking blood samples and doing analysis. However Twilight gave a look at MacReady and asked in curiosity

"Um excuse me sir, but what is that and what are you doing?"

"Shut up!" MacReady answered and after that the results were shown. "Alright, your not assimilated"

Spike, with confusion asked "Assimilated?"

MacReady said with clarity "You know that thing you killed?"

Spike responded "Yeah"

R.J. said "They each have to ability to shapeshift, but to do that, they have to kill the original person"

Twilight said in shock "So basically like changelings?"

"What?" MacReady asked

"Their basically a species led by an evil queen that can feed off love and turn into anybody they want"

MacReady said "In that case, yes and no. Look ill answer you...shh do you hear that?"

"..Mac....Ready!!" a shout was heard

The group had turned to face and saw surprisingly an human medic, the 8 were shocked, but MacReady gave a look of suspicion.

"MacReady, we need help the other soldiers are in danger and need transport!"

MacReady, without hesitance, fired his shotgun at him, causing the medic to slowly reveal itself not as a human, but as another creature.

The fake doctor creature then roared and attacked and MacReady and the others had began to attack all around it and MacReady shouted at the girls and Spike

"BURN HIM!!!"

The girls heard him and Spike had breathed his fire breath on the creature and MacReady managed to finish him off with his flamethrower. After the "human" was killed, Applejack asked in shock

"What in tarnation was that thing!?"

"Look, we need to move its not safe here, get your stuff and if possible find a way out!" Twilight said

MacReady also said with a fearful look "Hey, is their any town nearby?"

Spike replied "Yeah, Ponyville, why?"

"We have to get there fast!" MacReady said

"Why?" Fluttershy said

"Because if that Thing reaches there, it's gonna kill everyone!, come on lead the way, HURRY!"

The group heeded and they led the soldier to Ponyville, all the while killing off more of the creatures in the process, Eventually they managed to reach the school and in the chaos, Twilight managed to evacuate the ponies and put them in the school and Twilight was told by MacReady that she was to not let anybody out unless he was told and she complied, fearing the Thing would be too much for her. Eventually the Young Six had come and saw MacReady with Twilight coming with them.

"Hey, Headmare Twilight, who's?..." Sandbar asked and MacReady immidietly aimed his flamethrower at him, frightening the Young Six

"MacReady, stop!" Twilight shouted

"Get on the ground kid, you all as well!, NOW!"

The Young Six complied and MacReady used the blood tester to take their blood samples as he did with the others and saw that they were all innocent until Gallus blood sample reacted oddly and Gallus said with fear as MacReady aimed his gun at him

"Wait, I'm not fake I'm real please!" Gallus cried

"Sorry kid, but it looks like....huh?" MacReady said and the blood tester showed an result and when shown it said it burned out.

"Your lucky this time, it must've taken long since your blood types of your species may have different reactions compared to humans."

Gallus said with relief "Thank you...what's your name?"

"MacReady"

"I'm Gallus"

"Look, you need to go, that Thing might kill you guys, yo kid, can you find separate rooms for everyone, HURRY!. "

"WHY are you so rushed to stop this creature so badly, it can just be for us" Twilight said

"You wanna know, here's your goddamn answer, if it kills everyone, it uses the town to spread more offspring and breed as a way to ensure they don't die out as they need to survive. And if it kills you, it uses your body to create offspring and turn you into another type of creature."

"Then let us help, we killed one"

"Shut up, ps you didn't kill it, the small dragon did, plus if you see him, keep him so somewhere perfectly safe even he can't leave."

"Twilight?"

Twilight and MacReady had turned around and saw three alicorns. These two were Princess Celestia and Princess Luna and Princess Cadance with her husband and thir baby daughter Flurry Heart with a guard (Who acted oddly, which MacReady saw). They looked at Twilight and gave looks at MacReady. Shining saw MacReady and said with distrust

"Who are you?!"

Cadance calmed her husband and said "Stop dear, I apologize, is something wrong"

"Wait, shush....." MacReady said as he moved to the guard

"What?" Luna asked

MacReady saw the solar guards eyes act oddly and suddenly fired his shotgun and the guard ended up roaring violently and grotesquely shifted and turned into Pace, the same creature that was killed by Captain Blake in the previous events when MacReady and Childs survived (not for long for Childs though). Eventually, the bullets that MacReady shot killed the creature.

"WHAT WAS THAT THING!?" Cadence said holding Flurry as she cried

"That's one of the things I'm here to kill, those types have to power to shapeshift, but must kill the original victim to copy them fully."

Celestia said with horror "But, how can it be..."

Rumbling was heard and MacReady saw another creature with U.S army fatigues and saw it was holding more ammo. He shot as it rushed him, but he was out of bullets. Before he could be killed, Celestia and Luna used their magic to incinerate and kill it. After this MacReady said with cynicism.

"How about we talk inside?"