For Your Eyes Only

Sometimes, a document is too secret to be marked TOP SECRET.
So they make those For Your Eyes Only.
The document only appears to the recipient. To everyone else, they don’t see anything.
Not even a sheet of paper. It’s printed using a quantum ink and paper from phase-controlled wood pulp that only activates one unique set of sensory-processing neurons.
The problem is that when an agent resigns, you don’t know it they’ve destroyed all their documents.
We could surgically remove their eyes, but that would be cruel, leaving them completely blind.
So, as a mercy, we just kill them.