Answer:
A precious fluid, thicker than water.
I pass before the sun, but make no shadow.
They have not flesh, nor feathers, nor scales, nor bone. Yet they have fingers and thumbs of their own.
What has a mouth but can't chew?
What surrounds the world, yet dwells within a thimble?
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.