As an electrical engineering student at Pennsylvania’s Grove City College in 2013, Jake Loosararian traveled to Costa Rica for vacation. One day, he and a college friend camped in a rain forest on the country’s Pacific coast and drifted to sleep on hammocks they brought from home, to the sounds of shouting monkeys and scurrying lizards. The next morning, Loosararian walked to a nearby public shower. While rinsing off, he watched a green lizard—a gecko—walk up the shower wall, and thought to hims...