Dimension of Miracles, a 1968 novel by Robert Sheckley, which was also my (unaccepted) answer to this old question. Maybe you will recognize one of these covers. Dimension of Miracles can be borrowed (for free but registration required) from the Internet Archive.
Plot summary from Wikipedia:
Thanks to a computer error, Tom Carmody, an unlucky civil servant, wins the main prize of the Galactic Lottery. Being a human from the Earth, he doesn't possess galactic status and shouldn't even be eligible. However, he obtains the Prize before the mistake is found out and is allowed to keep it. That's when his adventure begins, since, not being a space-traveling creature, he has no homing instinct that can guide him back to Earth, and so the galactic lottery organizers cannot transport him home. At the same time, his removal from his home environment has caused, by the 'universal law of predation', a predatory entity to spring into existence that perpetually pursues and aims to destroy him. So Carmody is forced to be on the run, and with the help of his Prize meets several well-meaning (but usually not very competent) aliens that attempt to find where, when and which Earth he belongs on. He ends up transporting from Earth to Earth: different phases and realities of his planet, which of course, is not in the time or condition he expects it to be.
"Your predator was born out of a personification and solidification of universal law. This predator can feed exclusively and solely on you. The creature is shaped as a respondent and complement to your characteristics. Even without seeing it, we can know that its jaws are shaped to bite Carmodys, its limbs are articulated to seize and grasp Carmodys, its stomach has the peculiar and unique ability to digest Carmodys, and its personality is designed to take advantage of the Carmodic personality."