4chan's technology board were, let's say, huge fans of Terry Davis, developer of TempleOS. One day during his livestream he said he could see the CIA operators while driving because they would glow in the dark.

Now whenever someone is suspected of being an intelligence agency operator, people reply with pictures of a literal glowing person. Usually happens when someone spreads FUD about technology that's believed to be secure. It is assumed that these agencies are running psychological operations in online communites with the intent to dissuade the use of technology that could defeat them.