The slip of paper that denotes the annual victim of the lottery is marked only by a single dark dot. This mark looks like a spot, a blemish on the blank page. Spots and blemishes are frequently associated with disease, and so the appearance of the dot symbolizes the marking of a person for destruction, as if he or she were diseased and unsafe to others. The marked slip of paper also shows the pointlessness of the lottery itself. It is created by Joe Summers with pencil the night before the lottery, and it is only this mark, casually made by another human, that determines the fate of a person. The commonness of the object reminds us that the marked slip of paper holds no power in itself, other than the power that the villagers give it by adhering to the tradition of the lottery.
Oye, your comment got me thinking.
"A black mark"
Reminds me of The Lottery short story.
https://www.litcharts.com/lit/the-lottery/symbols/the-marked-slip-of-paper
Great reference!