Figure 2. Morphology of Cthulhu macrofasciculumque by differential interference contrast light microscopy (LM) and scanning electron microscopy (SEM). (A) SEM showing overall characteristics of Cthulhu, including the posteriorly protruding axostyle and subanterior emergence of a bundle of flagella. Because they are bundled an exact number is hard to conclude, but 20 distinct flagella can be counted in this picture and in (B), which is a detailed view of the flagellar emergence. This flagellar bundle has an elongated shape, but others (e.g., G) appear rounded.
Etymology: The name is based on the fictional many tentacled, cephalopod-headed demon found in the writings of H. P. Lovecraft, specifically The Call of Cthulhu. The tentacle-headed appearance given by the coordinated beat pattern of the anterior flagellar bundle of Cthulhu cells is reminiscent of this demon. The name is supposedly impossible to pronounce as it comes from an alien language, but currently it is most often pronounced "ke-thoo-loo".
Did anyone else use the phrase about lurking at the bottom of the Mandelbrot Set other than Charie Stross? I think that is his (one of his) contribution(s) to the Lovecraftian genre, but want to be sure.
I don't think so, but I'm not a Mythos scholar (still got a fair SAN score).
Although I don't think he was the first one to make the connection between magic and math, I do think he was the first one to marry the Cthulhu mythos into it.
And Stross was definitely the first to run a "WILL IT BLEND?" experiment on math-as-magic, the Cthulu mythos, the BOFH mythos, and a variety of British spy thrillers. Good thing he's got a Blendtec brain.