Seeing an opportunity, Gunn joined another crew and persuaded them to head back to the island in search of the hidden treasure. When all they found were the skeletons of other men on Flint's craft, Gunn's new shipmates were enraged, and, as punishment for leading them on a wild goose chase, Ben was left on the island.
Ben survived over 3 years, living off goats, berries, and oysters, and craves cheese, the natural part of a Christian diet. Over the period of those years, he began to go mad, most likely from stir-craziness, traumatic memories from Flint's ship, or simply from being alone.
After 3 years, Silver returned with a new crew, including one Jim Hawkins, whom he crosses paths with when the boy deserts Silver and his crew. Trusting the boy, but only a little, Ben knows what Silver is capable of, but is willing to help Jim to find the treasure, which Gunn has been hiding for the 3-year period.
After being given a cake of cheese by Doctor Livesey, Gunn kills one of Silver's men with his spear as a warning, and even attempts to scare his former crewmate off by imitating Flint's voice. Recognizing Gunn's voice, Silver fired his pistol, but missed. They meet again in the treasure hoard, but Gunn has little interest in the treasure, only siting on top, reading his copy of the Bible.
The fate of Ben Gunn differs in 2 versions: In the book (And most other versions), Jim promises Ben that Doctor Livesey will take him with them once they got off the island, and, keeping to his promise, Gunn joins them. However, in the 2012 Syfy version, Ben remains on the island as he wishes, fearing for what would happen if people found out he was once a pirate.
Ben appears, in the 2012 version of "Treasure Island", as, when you see him in the flashback, with short brown hair, fair skin, and bright blue eyes. He wears a feather in his headress, and wears light browns and dark reds.
3 years later, Ben's appearence has changed: His hair has become longer (But the feather remains in his hair), his skin is more tanned, and he has decorated it with white paint. He only wears a pair of old brown pants, and nothing else, save for small rings on his ears. His weapon of choice is a spear, which he uses to murder one of Silver's men in the middle of the night.
Ben is a Christian as he explains in the novel, and calls Silver "the Devil" and plus, prays for forgiveness before slaughtering a goat for nourishment. He dreams of eating cheese again, telling people it's "a little slice of heaven". As Silver states, Ben is a Yank, short for Yankee, hinting he may be from olden-day New York or somewhere around there. He is very fast and smart, catching animals (And Jim) in a net for food, but, of course, releases Jim when he finds him. He has no interest in the treasure anymore, seeing how much misery it has brought him, plus his madness, which brings no benefit, only unhappiness in light of his unfortunate marooning.