How to see the mysterious running dog in "The Power of the Dog"

To viewers of Jane Campion's psycho-western #ThePowerOfTheDog:
Did you see the mysterious "running dog" image in the mountains of rural Montana (actually New Zealand)?
It's also described as a "barking dog."
Only Phil (Benedict Cumberbatch) and Peter (Kodi Smit-McPhee) can see it in the film, but a new making-of book by Assouline gives everybody a glimpse.
Is it a genuine optical illusion, digital trickery — or a supernatural presence?
"The Power of the Dog" is nominated for 12 Oscars at the March 27 Academy Awards. 🌓
@peterhowellfilm