The nearly contemporary setting and autobiographical backward glance from late in life suggest Vonnegut's earlier works Jailbird (1976) and Bluebeard (1987). Another detail is reminiscent of Sirens of Titan (1959), in which the reader learns that the purpose of the Earth and the life on it is to aid a Tralfamadorean space ship cross the universe with its vital message, "greetings." In Hocus Pocus, Hartke finds a science fiction story in the magazine Black Garterbelt (a reminder that truth often turns up in the most unusual places) that life on Earth may just be a breeding ground of germs as they evolve into forms able to withstand the rigors of space travel.