Grimus

"After drinking an elixir that bestows immortality upon him, a young Indian named Flapping Eagle spends the next seven hundred years sailing the seas with the blessing, and ultimately the burden, of living forever. Eventually, he grows weary of the sameness of life and journeys to the mountainous Calf Island to regain his mortality. There he meets other immortals obsessed with their own stasis, and he sets out to scale the island's peak, from which the mysterious and corrosive Grimus Effect emits. Through a series of thrilling quests and encounters, Flapping Eagle comes face-to-face with the island's creator and unwinds the mysteries of his own humanity."--BOOK JACKET.