The creepiest scene
To me the creepiest scene in Harry and the Hendersons is at the end when they take Harry back to the forest to let him loose.
All of a sudden several other bigfoot appear. They were standing still and were unnoticed until they started moving to greet Harry.
So the movie basically shows that if you are out in the woods in the Pacific Northwest you could be looking at a bigfoot and not notice them if they stood still.
Considering that several times I have had dreams involving rather hostile bigfoots I find that a really creepy idea and I sometimes remember that scene even when I am in much smaller patches of trees on the eastern coast thousands of miles away from the Pacific Northwest.