In the winter of 1318 EP, every mage on Gaera with even a remote connection to the astral (say, Mag 2 or greater in PhilSys) felt a powerful magical surge run over the surface of the world. The effects of this surge seem to have been inconsequential in the physical world, though any delicate magical experiments might have to be adjusted or scrapped and restarted entirely because of it.
Some months later, word would begin to trickle in to Igala of sailors sighting a massive object floating in the sky in the southern seas, slowly drifting from place to place. They'd say that it looks like a twisted mess of rock and vines. Never does anything, just floats around.
I'd be glad to answer specific questions about it.