A cat. You see, cats have nine lives... Now even though the death star is a huge laser that could decimate everything, if a cat has nine lives then it could respawn back where it died, instantly. Almost out of thin air. Now if you take the consideration that the laser last for 9 seconds, then it is safe to assume that it is impossible for the cat to respawn instantly, so therefore theoretically speaking the cat would respawn after nine seconds, only dying once.