What is the creepiest thing you’ve seen in the woods, or in the mountains, or in deserts, or caves, or in small towns, or in remote or rural areas or while on large bodies of water, or while on a aircraft or a nautical vessel?

What is the creepiest thing you’ve seen in the woods, or in the mountains, or in deserts, or caves, or in small towns, or in remote or rural areas or while on large bodies of water, or while on a aircraft or a nautical vessel?