Completely fictional creatures invented in the 1980's by the Church of Voodoo Pharmacology. The allegation was that crack cocaine smoked by pregnant women essentially caused
fetal alcohol syndrome, when in fact (as many doctors have
testified), the often-freakish babies born to crack addicts were the victims of serious malnutrition (as their mothers were often very poor and/or retarded) and of course fetal alcohol syndrome.
For absurd definitions see
crack baby.