A brutally strong drug, Fever was created in Mexico and imported to Gotham City by the crime-lord known as the Ventriloquist. It had a brief vogue on the streets of that city, but a combination of heightened security at the US-Mexico border and the intervention of the Batman soon brought that to and end.
Effects of Fever include a burning sensation, as if the user is on fire, although this is reported as being an enjoyable feeling. In addition, it removes inhibitions and shortens tempers, while also leading to somewhat megalomaniacal behaviour. In this, it resembles a stronger form of PCP, along with the maniacal self-confidence common to cocaine use.