Artist's conception of a grimflit
What is a grimflit? Good question. Wish I knew. Not sure I want to.
I began seeing grimflits when perusing long lists of files in The Thang's secret depths late at night. Out of the corner of my eye - or the bottom of it - I would see a quick flitter of motion, a dark shadow scuttering across the keyboard (usually) or up the wall (rarer). Always gone before I could focus on it.
They tend to come out more at night, but are no respecters of clocks. Sometimes I don't see one for a week or more, and then there will be grimflits all over. They obviously have their own agenda, and it's probably none of my business...