Players have been spotting (or claiming to have spotted) Bigfoot in Grand Theft Auto games since San Andreas. The same has held true for GTA 5, but now the hairy beast’s existence seems to be indisputable fact. Not only does he exist in Los Santos, but you can play as him.
Since the game’s last major title update, Bigfoot is accessible as a peyote unlockable, but you can’t just run to the peyote’s location and grab it, though: it’s a bit more complicated. Redditor rkRusty did some datamining, and found that specific conditions are needed to access the peyote. These are determined by weather, time of day and whether you’ve collected the other peyote collectibles spread throughout the map. Oh, and you need to have completed the main game.
According to the data mined by rkRusty, Franklin needs to visit the location on a snowy Tuesday morning between 7 and 8am with 100% game completion. That applies to the PS4 version, but it probably holds true for PC as well.