Answer:
Large as a mountain, small as a pea, Endlessly swimming in a water-less sea.
What is that you will break everytime you name it?
I am a precious little thing, dancing and eating all the time. Watch me from a distance, so you can feel my warm and gentle love. But don't come to close or my next meal you could be!
Until I am measured I am not known, Yet how you miss me when I have flown.
Left to right Iām quite bright. Right to left I might bite.
What is full of holes but still holds water?