Waggy's in her basket on my windowsill, growling at an excavator that's digging up the road outside.
That's almost like posting harsh spank anonymously online to strangers you hope you will never meet.
My cat does something similar when she sees a raccoon or a 'possum outside. (She has never had the courage to venture outside. I feel bad for her, but I am also glad that I can easily keep her safe from harm.)
It is entertaining to watch her ridiculous back arching, tail fur puffing, spitting, sideways stance and hissing at little more than a shadow.