I can be quick and then I’m deadly,
I am a rock, shell and bone medley.
If I was made into a man, I’d make people dream,
I gather in millions by ocean, sea and stream.
Sand. Quicksand is deadly (at least in movies). Sand is made up of rocks, shells and bones. The sandman visits you when you dream (again, according to legend, I’ve never seen him…) and there is plenty of sand in the oceans, seas and streams.