All stories need tension. For a romance, it might be the question of who will snare who. A novel set in high school might center on a team victory or an important test. In many other genres, though, danger to life and limb is one of the characters’ main concerns. What would a thriller, mystery, or fantasy be without people dodging bullets or arrows? The reader will invest nothing in the story if they don’t think the characters are in serious danger.
This presents a problem. Writers need to show that the escapades in their story are dangerous. If the main character skips through four death traps without a scratch, no one will take the fifth one seriously. By virtue of being the story’s focus, he/she is invincible.
On the other hand, you can’t main your MC too badly. Killing them (unless it’s at the very end of the story) is also out of the question. At least it used to be.
See, writers of books, TV, movies, you name it, hit upon this simply brilliant idea. Why not kill someone temporarily? The character dies, showing how dangerous things really are as well as hopefully eliciting horror and anxiety from the audience. Then some loophole is triggered – magic, CPR, time paradox, etc – and they pop right up again. No harm done. Now the stakes are shown to be high and you’ve still got a functioning MC. Perfect, right?
Maybe. Used sparingly, this plot ‘twist’ can work well. Unfortunately, these days everyone exploits it. Almost every final showdown has heroes falling in droves, only to jump up shouting “I’m ok!” five minutes later. What used to be a surprise and a relief has become run of the mill. It’s so bad I was driven to complain, “No one ever stays dead anymore!”
I’m not saying that this trope should never be used. For better or for worse, the “I got better” phenomenon has become widely accepted. Just take care not to overuse or abuse it. Cheating death too much will cheapen it.