When you think about the relationship between famous heroes and their biggest rivals a question naturally emerges: what happens when our favourite superheroes get pushed too far?
Because where villains can kill someone just for the sake of it, for heroes this matter is far more complicated. With the majority of costumed crusaders having moral codes and limits to restrict them, it takes just that little bit extra for them to actually murder someone - even if that someone is their most hated rival.
Generally, this means any comic containing a murderous hero also contains some epic slight against them, that finally prompts them to take that route they've avoided for so long, and finally crush those who have conspired harm against them.
Or, alternatively, you could be Moon Knight, and just rip a man's face off without any sort of ethical quandary - although even that comes with its own special set of ramifications.
While these deaths often last for a hilariously short amount of time, they still always have a profound impact on the story, either by effecting the hero, or by depriving a given comic of a longtime adversary.