I am at liberty to disclose this. I was travelling with a family member through the Nez Perce reservation in north/central Idaho. Said family member at the time enjoyed wildlife photography, so when she told me to stop so she could take some pictures, I would accommodate her. It was at one of the many creeks that flowed into the Clearwater River where she demanded rather emphatically that I stop. I did. And I didn't even say anything when it looked to me like she was frantically photographing a big pile of underbrush across the river.
None of those photographs turned out well, so I asked what she was trying to photograph. She told me. I just shrugged and said, "If that's what you saw, you'd be far from the first to have seen it there."
She didn't know at the time, but that little creek is known as Skookum Creek. For those of you who don't know, the word doesn't just mean big or strong, but is also a Chinook name for a being like what the coastal Salish more famously call Sesquak, or Sasquatch.