Crack.
One of them makes crack while the other just markets it.
To carry his library card.
A drug is a substance which when injected into a guinea pig produces a scientific paper.
I SEE IT!** ooooohh **I NEED IT!**(https://www.youtube.com/watch v=Ps0MfBG5-Uo#t=1m24s)
Yello?
Shellular*, of course...