G-13, or Government Indica Strain 13, is a pure indica with mysterious origins, hence its cryptic name. It's been reported that this potent strain was bred by the CIA, FBI and other intelligence agencies at the University of Mississippi, after they collected the most potent indicas around the world. The story goes that one of the agents removed a cutting from the lab and leaked it to the public. While this story is entertaining, it's probably not true. 
 
G-13 is reported to give off a powerful, sedating body high, making it optimal for nighttime (and for more experienced consumers). People have reported that it smells like citrus and oranges, with earthy, sweet aromas.