SPANK
SPANK is a drug first mentioned during the Grand Theft Auto III mission Don't Spank Ma Bitch Up, where a local thug is supplying Luigi Goterelli's prostitutes with the drug, which Luigi feels is bad for business. The drug is produced by the Colombian Cartel and is brought into Liberty City through several ways, including "Chunky" Lee Chong selling it at his stands in Chinatown or the Columbian Cartel itself selling it at booths disguised as espresso stands. This drug is most likely either cocaine or based off cocaine (as the hidden packages in Liberty City are cocaine filled packages).
In Grand Theft Auto: Liberty City Stories, Rise FM DJ Boy Sanchez says that he tried out a new drug on the streets called SPANK which proves that the drug was present at least since 1998.
In one mission several "Spanked-up madmen" with bombs attached to their chests attempt to kill Claude in the Liberty Tree parking lot, a plan devised by the Uptown Yardies and Catalina.
There is no clear, concise evidence that this drug was manufactured before its mentioning in 1998, but it is thought that it, or something very similar, can be seen in 1986, as a Distribution mission in Grand Theft Auto: Vice City may be used to sell a SPANK-like drug to citizens.