A man walks into a bar.
Suddenly, there is a knock on the window.
The man turns around to see who is knocking, but there is no one there.
A few minutes later, there is a second knock on the window.
Again, the man turns around and he doesn't see anyone there.
The man starts to get nervous. He reaches for his phone to call the police, but before he can dial the number, there is a third knock on the window.
The man is so scared that he nearly dies.