This story is a sequel to Chest pains
(The pic is from Samaru163)
(This is a full successor to Chest pains)
The white changeling, despite being a creature hellbent on erasing existence, has created a hive of its own by morphing ponies that pass by it, and by subjugating lone changelings wandering about haphazardly. However, after seeing a blurred picture of Chrysalis within the hooves of some captured explorers, its chest has begun to hurt it tremendously.
Needing to learn about what this sensation is, the creature has left its hive in the large forest to find the fabled alicorn of love: Cadance, determined to have her teach it "emotions", before these "things" destroy it from the inside.
Then again, how is a changeling supposed to learn about emotions, let alone one created without them to begin with. What is going to happen to the denizens of Canterlot while Celestia and her sister are gone, and the only to watch a being capable of erasing you from existance in one fell swoop are but a handfull of ponies, including a young alicorn and her husband?