Add a link to an article or other coverage of the mystery if you can.
Here’s one: The Max Headroom signal hijacking incident
In 1987, two individuals hijacked television signals of two TV stations at night and broadcasted creepy footage of someone wearing a Max Headloom mask and costume to viewers. They were never identified.
I think reading up on this has made me more appreciate the profoundness of that Arthur C. Clarke quote
The possibility of being alone is not just terrifying in and of itself. Its horror is also in mulling over why we might be alone.