Genetics: Grape Cream Cake with Grandpa's Gun Chest Grandpa's RPG is an indica-dominant strain created through crossing Grape Cream Cake with Grandpa's Gun Chest. This strain has a rich musky flavor with overtones of earth. The aroma is just as funky with notes of skunk and a woodiness throughout. Grandpa's RPG is known for its calming and sedative effects that make it perfect for unwinding in the evening or relaxing on a lazy day off.