Snake in the grass, or in the water, or elsewhere

I thought it was a snake. Crept up as quietly as I could to get a pic, and I was so pleased with my stealth (the snake didn't move, so I must have been very, very quiet).

For years I've kept a rubber snake in my vegetable garden, because I was told that it would scare away squirrels. (Note: nothing scares away squirrels). Every time I walked through the garden, there was a nanosecond when I thought that rubber snake was real.

The trouble with human perception is that it often causes us to...