The powerful high may be sedative, so if you’re looking for a new couch-locking OG cultivar, give Nightmare OG a try. A cross of OG18 and White Nightmare, Nightmare OG was bred by Sin City Seeds to celebrate OG18, one of their favorite strains from DNA Genetics. The result is a strain with blueberry and lemon notes mixed among a piney OG….  The result is a strain with blueberry and lemon notes mixed among a piney OG.