A dead god still dreams.
The newly graduated pony Foot Note (specialising in research of bygone civilisations) is rapidly headhunted by a team of Celestia's finest scientists and is granted access to a colossal vault beneath the grounds of Canterlot. Here, he is informed of a fact that both elates him and forces him to revaluate his research.
An example of a long extinct race has been in Celestia' ownership for well over a millennium.
And it's still alive.
Millennium is a cosmic horror My Little Pony fanfiction that rather unusually portrays Humans as a lovecraftian styled abomination, who's origins are not yet fully explained. Following Foot Note's induction into Celestia's private research division, it displays the young researchers predictable glee at the opportunity to potentially make history, whilst demonstrating the mental decay caused by the attempts at researching and containing something the team is in no way prepared for. Worse still, the efforts made to discover the creatures origin and even the most minute facts about it worsen the dire situation, waking up a vengeful being.
The story can be read here
This fic features the following tropes:
- The Corruption: It is hinted that Luna's original attempt to delve into the humans mind was a key factor in her becoming Nightmare Moon as his darker thoughts bled into her mind. Also, the humans effect on Equestrian surroundings is characterised as a corrupting 'rot' across everything.
- Humanoid Abomination: Though outwardly human, the Millennium clearly has shifted beyond the rules of actual humans, being hazardous to life, and driving ponies mad over prolonged periods.
- Person of Mass Destruction: The titular human entity 'Millennium' has access to vast reality warping powers that break down life itself, only being held in check by his cell that appears to have once been part of a seed vault. Plus, he managed to survive whatever left the rest of humanity extinct.
- Things Man Was Not Meant to Know: As stated above, Luna's attempt to look into the human mind made her completely break. Later, a griffin called in as a second mental probe is at first merely confused by the mental landscape of a human, before almost being destroyed when it attempts direct contact.