I vibrantly fluff up your bags and gifts, I anchor your muscles and repair rifts, I float through the air when I catch a breeze, And stop the explosion of your sneeze.

Used to carry liquid and solid, As well as some sporting lids.

Built of twigs and tucked away, I keep small eggs safe night and day. Though I am not a house by name, for many birds I serve the same.

Cat six, in four pairs, whisks me. In turn I bring infinite pups and kitties.

I ask no permission before I descend. I hide sharp edges and blur where things end. I have sheltered kings from winter's bite, And spared their allies from judgment's light. I may silence a mountain beneath silent white, Or smother dissent with a single decree. Whatever lies beneath me, Soon becomes harder to see. What am I?