The TVTropes Trope Finder is where you can come to ask questions like "Do we have this one?" and "What's the trope about...?" Trying to rediscover a long lost show or other medium but need a little help? Head to Media Finder and try your luck there. Want to propose a new trope? You should be over at You Know, That Thing Where.
Just the "accidentally sorted into House Lannister instead of Stark" part, not the whole thing, in case I was unclear with that reddit title.
never heard of that trope, but I can tell you that a trope that's "described as a cliche more than I've actually heard of it in the wild" is what's called a Dead Unicorn Trope, which is a snowclone of Dead Horse Trope, the place we stick tropes that have become cliches even by our standards.
I've seen this described as a cliche more than I've actually heard of it in the wild.
Basically, the protagonist thinks they are [X magic], but they are actually [Y magic].
Here was what made me think of it, a Reddit thread on /writingcirclejerk: "Young Katniss thinks her acceptance to Hogwarts School of Jedi Training will enable her to use the school's TARDIS to destroy the One Ring. But things get complicated when she's accidentally sorted into House Lannister instead of Stark".
Is this a trope?