In thread 8, a certain changeling was revealed to be alive. One thought dead, and lost. 88 had survived the caves.
And she was not alone.
Spores of a mushroom from a time long past, ones that had driven another Queen to madness and was thought gone forever, the Cordyceps, followed with her, and it had combined with her, merged into one and kept her alive after her drowning. More than that, the Cordyceps had mutated with her insect nature, gaining new knowledge and insight, and with it's new freedom sought only one thing.
After months of wandering around and leaving hidden spores everywhere, a failed infusion is spilled on Eighty Eight in thread 47, and allows the Cordyceps to jump to ponies and take them over. The result is a infectious spores that can use Changeling shapeshifting on a molecular level, meaning they can regenerate from any wound instantly no matter how grievous. With this, they become unstoppable.
Soon, almost every other city is taken over, excepting those in the snow and Canterlot.
Canterlot is the last stronghold invaded, and they must fight back against the unstoppable horde.
First mention of 88 and the Cordyceps here https://archive.moe/mlp/thread/16501328/
First attack here 47: https://archive.moe/mlp/thread/20365095/
Canterlot invasion begins here https://archive.moe/mlp/thread/20580492/
- This had the longest gap between setup and payoff, at almost 40 threads between.
- Chrysalis's streak of being hospitalized at the end of an arc continues with this one.
- This arc is when Chitania was cleared of all crimes in Equestria. Empahsis here is on EQUESTRIA. She can be still be be charged, incarcerated or worse in other countries.
- Applejack rode a dinosaur changeling... that is all.