In the world in which Air Ponyville takes place, changelings are a living weapon that never saw a war. They’re mostly human, but with heavy infusions of octopus, spider, and insect genetic traits thanks to reckless unsupervised mad science, with a cybernetic control unit mounted on their skull and wired into their frontal lobe. They’re capable of changing the color and tone of their skin and hair, and have some ability to alter their height and apparent weight.