What is reef drug?

Excuse me, but I'm a bit confused by the term "reef drug." Could you please clarify what you mean by that? Are you referring to a specific type of illicit substance that is somehow associated with coral reefs? Or is this perhaps a colloquial term for something else entirely? If it's a specific drug, could you provide some more context or details about its use, origin, or effects? Alternatively, if it's a misunderstanding or misnomer, could you explain what you actually meant to ask about?