Answer:
What can be swallowed, But can also swallow you?
There is a creature of God whose body is hardΝΎ it does not wish to eat unless you strike its head.
There is an ancient invention. Still used in some parts of the world today. That allows people to see through walls.
In your fire you hear me scream, creaking and whining, yet I am dead before you lay me in your hearth.
What can be heard and caught but never seen?
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.