Shadow and light.

[Naita]

I'm as small as an ant, as big as a whale. I'll approach like a breeeze, but can come like a gale. By some I get hit, but all have shown fear. I'll dance to the music, though I can't hear. Of names I have many, of names I have one. I'm as slow as a snail, but from me you can't run. What am I?