I’m certain I’m not the first to try this, but for some reason I got to playing with the shape mask parameters in conjunction with exposure compensation. “Interesting” results, although I can almost hear the equations screaming in pain… 
Too much time on my hands apparently.
The image is just a throwaway test shot I took across the street from my house. Certainly no artistic value in anything here.
There are of course an infinite number of stupid things you can do. If you’re interested in wasting time, here’s my starting point. Just rename to match your raw.
Stupid_mask_tricks.arp (12.2 KB)