Somna
From Warhammer 40k - Lexicanum
Synthesized out of pollen extract from the Nephyis Orchix of Iocanthos, Somna is a potent medication that induces a coma-like shutting down of vital functions and brain activity. The subject appears deceased to all but the most thorough of medical examiners, and can survive in this state for weeks if properly dosed. Its medical application has a darker side, as it is also used to evade capture by feigning death or to subdue victims of kidnapping.[2]
Turned into a recreational drug by overworked menials[1], Somna is also the basis for spiral black, a highly dangerous variant of Obscura concocted by some of the gangs in the Sibillan underhive.[2]