A large swamp

You are standing barefoot right at the edge of a large swamp.

You squint, angle your head and start to go cross eyed as you try to gauge how large it is but it's difficult to tell, it's quite hazy and seems to play tricks on your eyes, but you are fairly sure it's less than 50 meters across. The swamp extends to your left and right as far as your eyes can see.

You look down at the swamp itself, it's filled with a thick tar like substance.

"Probably liquid rubber," you say to yourself. You squat down at the edge of it and dip a finger into it. it comes out coated in a thick dark gray liquid that quickly dries off to form a semi rigid finger glove. You manage to peel it off easily after you decide to remove it.

You stand back up and look around, then something grabs your attention.