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Here's one: The dragon actually doesn't eat/kill the princess, and he may even be her protector. Subversion?
I think that's an example of an aversion. If it looked like the dragon tried to kidnap or eat the princess and it turns out the dragon was actually trying to do something else, then that's a subversion.
Playing with a Trope. See if that helps. It may be an Inverted Trope.
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How well does it match the trope?