Gracie and Zarkov were pseudonymous writers who documented their use of dimethyltryptamine and other psychedelic tryptamines and phenethylamines.
[1][2] Their experiences were documented in self-published papers, as Notes from Underground,[3] and in articles published in outlets such as Mondo 2000, starting from ca 1980s.
According to Sisters of the Extreme: Women Writing on the Drug Experience, Gracie's name was chosen in homage to Gracie Allen, Grace Slick, and the "gratuitous grace" that Aldous Huxley found in the psychedelic experience.
[4] Zarkov is a likely reference to the fictional professor Hans Zarkov from Flash Gordon.