After Chrysalis, the Former Queen of the Changelings, lost her hive, she became vengeful and spiteful. She wanted Equestria, the Mane Six, all of Ponykind to suffer, not caring about feeding off love no more, just wanted revenge. She made a powerful curse, like an infection, that turns healthy ponies into changeling mutants, under the hive control of Chrysalis. She is ready to take over Equestria with her new hive. And any that remains, survivors, will be her love farm, to feed off their love.