In the past I've said things like " Coffee ninjas will get you!"

I keep toying with the idea of a one off comic book or a 4 minute movie about Coffee Ninjas who exact vengeance on those who are awful to baristas.

And said ninjas have the ability to travel inside the aroma of coffee- so wherever there is the smell of coffee, they can use that as an entrance or exit point.

Other than their martial arts skills they can turn regular to decaf in an moment. And vice versa.