I remember,

the first day I saw him. A black van, driving down my street, turning a corner, and bringing up his phone. A sharp painful sound filled the air, and ever since, he's been tracking down my friends and family one by one. Each time someone sees him for the first time, they report hearing that same sound. Then, he never leaves. He follows them day and night. I escaped him once, when he tried to run me down. He's still following me.