The first chimera was created by Quanta after a magic accident in Stable 24's school. It is a hodge-podge assortment of various animals kept as pets in Stable 24, resulting in a vaguely feline reptile with oversized fangs and cat-like eyes with horizontal slits.
Stable 24 chimera.
~ 
Cazra
History[]
The Stable 24 Chimera are the result of a magical accident. Created from a hodgepodge of animals kept as pets by the vaults residents. A powerful Unicorn filly named Quanta accidentally fused several classroom pets together. Unfortunately, she also fused an insect of some kind.
The unique biology of the creature soon became apparent when it attacked the residents of Stable 24. The bite of a Chimera is poisonous, much like a Radscorpion sting, and will begin to affect a victim fairly quickly. They are also fast breeding due to the number of young that can hatch from a single brood of eggs, inside a victim. They completely overwhelmed their Stable long before anypony in the wasteland entered the Stable.
Littlepip and Calamity encountered the Chimera when they were sent to seal up the vault and stop them getting out. Calamity was bitten by one, but was saved by the cure developed years ago. Littlepip and Calamity discovered the Chimera had an aversion to water and couldn't swim, which was why they hadn't spread across the Wasteland. Stable 24 was located near a river halting them.
Once Calamity was cured, the two ponies escaped Stable 24 and diverted the nearby river so it would flood the Stable and kill the Chimera. The Chimera are now most likely extinct.
Biology[]
The Chimera have the appearance of a cat, snake, reptile hybrid. Chimera have large fangs which they use to bite victims. Not immediately apparent, the chimera has insectoid elements, and can inject five or so eggs as well as magical toxins as it bites a victim.
Victims of bites will die within a day, either from the poison or the eggs. The eggs will begin to hatch, and the Chimera offspring will eat their way out of the host.
Chimera bodies aren't designed for swimming, and a typical Chimera will drown if it tries swimming across a body of water. The river near Stable 24 prevented the Chimeras from spreading out into the wasteland and this allowed Littlepip to drown every Chimera in Stable 24.
Notes[]
- One of the few Abominations, not created by Taint or Balefire Radiation.
- Lacked the ability to swim.
- Very similar to the events of Vault 22 from Fallout New Vegas.
- They are likely a reference to Nightstalkers; a hybrid creature of coyote and rattlesnake in Fallout: New Vegas. With elements of Cazadors (a giant insect, also from New Vegas) which were mutated from the Tarantula Hawk Wasp and procreates by injecting its eggs into taratula spiders.