This essay investigates a sea voyage in Book II of Edmund Spenser’s Faerie Queene, to which scholars have seldom paid much attention. I argue that the aquatic life forms the Knight of Temperance encounters on his journey shows Spenser’s investment in natural history, a leading force in the scientific culture of his day. By deploying original research, I assert that a careful examination of this passage shows Spenser’s theorization of extreme life, thereby anticipating our modern scientific focus on extremophiles, temperate environments, and the search for extraterrestrial life. This paper ends by proposing that a philosophical conundrum lies at the core of discovery, leaving humans once again questioning their status in the universe.