This story is a sequel to Celestia is still a Spider and Chrysalis hasn't been Informed

The day prophesied to be that of Sombra's return is nearing. The Cutie Map has sent Twilight and Rarity on a mission to Canterlot, and the two can't seem to find the problem. A mysterious force lurks in the background, trying to stop the purple alicorn. Time is quickly running out, and Rarity is the only one who can figure out what's happening and put a stop to it before it's too late,

Also, Celestia is a giant spider, but when you look at it that fact isn't really all that important in the scheme of things.

This story is a sequel to Celestia is still a Spider and Chrysalis hasn't been Informed

Celestia is a spider. That is the one truth, the one irrefutable principle that rules over Equestria. Society, as it is known to modern ponykind, is built and shaped by this and this alone. No one, not a single pony or creature, dares challenge the notion that she who moves the Sun has eight legs, six eyes, two fangs, and is in fact a giant spider. For it is the truth, and everyone knows it.

Audio reading by Lotus Moon.
Russian translation by MLPMihail.

This story is a sequel to Celestia is a Spider and That's pretty much It

One day, Celestia had woken up as a spider. A rather curious event, but one the Princess had approached with a surprisingly calm attitude. She'd decided to take no further action than that of informing her subjects of the fact that she'd changed, and to simply continue her life.

In a rather unfortunate turn of events, the Changeling Queen herself, seeing as she was not considered to be one of Equestria's citizens, had not been informed of the occurrence. This led to a rather awkward situation when she met Celestia for the first time after the transformation. Celestia found that encounter to be quite entertaining. Chrysalis didn't.

Audio reading by Lotus Moon.
Audio reading by Pony&Wolf Productions.
Russian translation by MLPMihail.

On one morning, without explanation, Princess Celestia woke up as a giant spider. Her guards, her sister, her once student Twilight and the rest of her ponies and other creatures of Equestria were rather shocked at the fact that such a transformation had taken place in her.

She didn't seem to mind it.

Audio reading by Lotus Moon.
Polish translation by Dolar84.
Russian translation by MLPMihail.