Answer:
I am heavy forward but backward I'm not.
I am a creature with a βtightβ name.
I am full of holes but still holds water.
Poor people have it. Rich people need it. If you eat it you die. What is it?
I am a portal to another world which you cannot enter. Only you can see me but I can't see you.
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.