There’s nothing quite so shocking and scary as when a hair-covered, eight-foot-tall giant shows up and disrupts your life. That happens multiple times in “Sasquatch Short Stories,” a set of 15 unsettling tales by Don Shearer, a Literary Titan Book Award winner who has written three previous books on the subject. In these fictional stories, people of all ages, walks of life and areas of the country run into their region’s Sasquatch, the legendary beast of the forest — a true apex predator — and their lives are completely upended by their close encounters with the huge and mysterious creature.