>why and how would Sam come up with such a pretty morbid scenario in the first place? (Uh, no, I can't answer that either. :)

After being chased by Nazgul, surviving attacks by trees in the Old Forest and by barrow-wights, and seeing Frodo wounded by a magic weapon -- not to mention witnessing cruelty to an animal, probably for the first time in his life, at Bree -- how would Sam not have death on the brain?