Answer:
Once you know it exists, it no longer exists. What is it?
Everybody's got one.
You roll it or you buy it, People say you shouldn't try it, Because you may get a stroke, From inhaling all that smoke.
Cold head and feet; Round as a ball; Always turning around itself.
This sparkling globe can float on water. It is light as a feather, but ten giants can't pick it up.
If it’s information you seek, come and see me. If it’s pairs of letters you need, I have consecutively three. What am I?