I finally saw Uzumaki last night. Really great, better than I had expected. The plot concerns a small town where the idea of the spiral has infected the minds of its inhabitants. I love plots that involve mind viruses. Christopher Cherniak’s “The Riddle of the Universe and Its Solution” has a particularly good one: students and researchers studying the brain and consciousness begin falling into comas when they encounter the equivalent of Godel’s incompleteness theorem for the human mind.
Closely related are plots involving ideas so sublime they destroy their receivers, or videos so pleasurable/horrible to watch they destroy their viewers. Both Infinite Jest and Ringu made use of the latter.
As a plot device, a thing which will spread inexorably by virtue of its intrinsic structural properties makes for a compelling story. I was always fascinated by the idea of ice-nine for that reason. Prions, too.