Zombies vs Changelings

"Breaking news!" Every TV blared in Ponyville, maybe even Equestria even "After an accident at the newly built science facility, all citizens are to remain indoors unless by a Royal Guard until further notice! REMAIN CALM!". Rainbow Dash was bummed when she heard that because now she was stuck in Sugarcube Corner with Pinkie Pie for the moment. Pinkie Pie just laughed her troubles away like she always did.
"Oh come on Dashie. What could go wrong?" Pinkie Pie assured her old friend. Rainbow Dash just calmed down, but was still upset that she was told not to leave the building. The pegasus just looked outside to see what the big deal was. She saw that nobody was in the streets. Funny enough because she could actually hear something coming from outside. Something sounding like hoof steps and moaning from outside.
"Pinkie, is this another prank?" Rainbow Dash asked, concerned about what's going on.
"Rainbow, I told you once, and I'll tell you again. CALM DOWN!!! This isn't '28 pranks later' you know!" Pinkie Pie said, yelling at Rainbow Dash, confused by the reference Pinkie made. The moaning and hoof steps came closer and closer. Soon enough, the sound would worry even Pinkie. Rainbow Dash went out to the back door, peered out the window, and at first saw nothing. Then it struck. A dark grey, scarred hoof smashed through the window, clawing its way to Rainbow Dash's face, which was just out of reach. Rainbow peered through the smashed window and saw the hoof was belonging to a body that appeared dead, but walked as if it was still alive. It's glowing dead eyes peered back into the violet eyes and saw Rainbow Dash as a delicious meal for the ghoul to devour. Rainbow Dash let out a small gasp and hid in another room.
"Please tell me we have weapons." Rainbow Dash asked, panting. Pinkie wondered why she would have any, and Pinkie peered back and saw the undead corpse punch through the back door more and more times. Pinkie's eyes shot out of her head as she let out a small, frightened screech. The two ponies held each other, shivering, scared, and hopeless. The zombie broke down the door and shambled on over to Rainbow Dash and Pinkie Pie, followed by other zombies waiting to eat.
"Screw it!" Pinkie Pie yelled as she and Rainbow ran on over to the front door. The lead zombie sprayed a green toxic goo at Rainbow Dash. The goo burned her skin as if it was lava, or maybe it made Lava feel cool in comparison to the goop. Rainbow Dash screeched in pain as the goo drowned her in agony.
"Dash!!!" Pinkie yelled as she finally got the door opened "I'm not gonna leave you to die!". Pinkie tried to drag Rainbow's body out the door. The lead zombie bit Rainbow Dash on the leg, spewing blood all over the walls and the floors. Rainbows screams echoed all across town. There's no denying she was infected.
"You already did." Rainbow said, calmly accepting her fate. The green ooze leaked and fused with her blood. There was no point in fighting the infection within her body. With that moment, Rainbow Dash closed her eyes, and breathed a final sigh. Pinkie Pie ran, and the last she saw of Rainbow was her body shooting back up, with a darker grey shade of blue and glowing green eyes.

Pinkie Pie cried as she ran from the carnage she just witnessed. One of the other zombies caught up to Pinkie Pie, and was ready to spread the same ooze on Pinkie before biting her and submitting her to the infection. Before Pinkie could even recognize who it was that was that was infecting her, a silver bolt shot out of nowhere, covering Pinkie and the zombie's dead body with the maroon blood of the zombie's original body.
"Y'all right sugarcube?" A familiar voice called out. It was Applejack, who managed to build herself a crossbow. Pinkie smiled, tears trickling down her face, as she jumped up and hugged her friend. Applejack hugged back, tears falling from her eyes as well. Pinkie stopped hugging her and brushed the blood off of her already stained coat and hat. The zombies walked slowly to Applejack and Pinkie Pie, reminding them of their situation. The two ran for an old abandoned safe-house Applejack made in haste of this apocalypse.
"Was anyone with you when you were attacked?" Applejack asked Pinkie Pie, reloading her crossbow. Pinkie can't stand and have flashbacks of the attack.
"Well, there was Rainbow Dash, but she...died...trying to escape from me." Pinkie said. Once again, tears down her eyes. Applejack almost shed another tear, recollecting all the good times Rainbow Dash had with her in life.
"Well, at least there's 7 of us now. There's me, you, Twilight, Fluttershy, Spike, Starlight, and--" Pinkie said, trying to cheer the two of them up, but was interrupted by Applejack, who started crying quietly. Something happened and Pinkie just knows it.
"Is there...someone who's not with us?" Pinkie Pie asked, cautiously. Judging by the look on Applejack's face, she suffered a fate similar to Pinkie Pie's.
"I was at the Carousel Boutique with Rarity when we were attacked. They came in through the windows and burned us with a weird goop. Rarity...didn't make it." Applejack said with each sniffle and tear as she pulled out a necklace Rarity gave her earlier. "This is all I...all WE have left of her". And with that, the cowgirl burst into tears once more, unsure of a plan.

"Well, we can't just sit here. We have to make a stand. We have to fight. We have to--" Pinkie Pie proclaimed at a small grey-purple hand extended, exposing the base. They recognized the body as someone they knew, but they were afraid that whoever it was, not only became infected, but exposed their hiding spot. Spike was zombified as well, followed by the zombified corpses of Rainbow Dash, Rarity, and almost 25% of Ponyville.
"RUN!!!" Pinkie Pie said, yelling to finish her sentence. On the run, Applejack found a broken splinter in the walls of the hallway. Applejack ripped out the plank of a splinter and gave it to Pinkie Pie as a weapon for her to use. The zombies trudged across, closer and closer to Applejack and Pinkie Pie. Applejack fired her crossbow, causing an explosion in one of the zombie skulls, causing a bloody explosion. Shortly after, another one of the zombies sprayed its mysterious goop once more, and the goop landed on Pinkie Pie, burning her as if her skin were falling off. Pinkie Pie screamed in agony, and fell onto the floor.

"I'm not giving up on you Pinkie!" Applejack said as she picked her up and ran father away until they spotted an old elevator. Applejack put Pinkie's injured body on the ground and pulled the rusty lever. The doors to the elevator shut before the zombies could get to them, and hoisted Applejack and Pinkie Pie up until they reached the top floor. They found the elevator lead to a mining cave nearby to Everfree Forest, which meant one thing for the survivors: Fluttershy's nearby.