Black Shuck is a giant black dog from the folklore of East Anglia, England, described with a single flaming eye. Those who see it are said to die within the year. In 1577 the legend gained physical weight through scorched claw-marks said to have been left in a church.
In that seeing it becomes a death sentence and its trace remains as matter, it shows a structure where what is seen seals the fate of the one who sees.