Crunchy goodness: 2
Spinoffs/Sequels/Copycats: After millions of people bought Superman #75 thinking it would some day become incredibly valuable (ha), tons of other superheroes "died" or became paralyzed or turned out to be clones. More recently, animation diva Bruce Timm put out a straight-to-DVD adaptation called Superman: Doomsday.
Elevator pitch: What if someone punched Superman really really really REALLY hard?? No, no, harder than that. A whole bunch of times. What then?
Deadliest spoiler: Superman comes back from the dead, but he pays a terrible price. He's stuck with a disfiguring mullet.