Answer:
Said to have fifty shades
I occur twice in eternity. And I'm always within sight.
It goes up and down the stairs without moving.
This sparkling globe can float on water. It is light as a feather, but ten giants can't pick it up.
What pulls you down and never lets go?
I repeat only the last word you say. The more I repeat, the softer I got. I cannot be seen but can be heard. What am I?