In William Gibson's Bridge Trilogy, dancer is an addictive drug used in the near future setting. The books take place in a semi-dystopian future, and a properly noir drug is needed to make the setting complete.
William Gibson's writing is certainly atmospheric, and often he uses realistic details to make his science fiction seem more plausible. Dancer, a drug that is mentioned in passing, is one of these details. The drug is described as having slight hallucinogenic qualities: "a faint aura around every source of light now", many stimulant qualities: "It was there to allow you to do things...and finish them", and a disassociative effect: "Trouble could look abstract". It had side effects of paranoia, and hypertensive crisis. Its means of administration, rubbing into the gums, is a little odd, but that could be a variant of sublingual administration.
The details of this drug make it seem like a complex amphetamine, such as MDMA, only with more of a stimulant effect, and less of a hallucinogenic or emotional effect. It is a fairly accurate description of what MDMA would be like in a noir, cyberpunk world.