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.
No, that's more for actual covers.
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I don't recall one specifically for the synopsis but maybe take a pass at the Advertising tropes? I think it's a bit tough because the synopsis on the back of a DVD or the inside flap of a book is supposed to entice you to read the story but not give the plot away. I can't think of examples where the synopsis outright lies though, especially if it is telling you the plot.
https://tvtropes.org/pmwiki/pmwiki.php/Main/AdvertisingTropes?from=Main.CommercialsTropes
Never Trust a Trailer covers lying blurbs. You might also check Lying Creator.
I was never here, and you never saw me.
Tropes Are Flexible, but more like Never Trust a Trailer.
Becky: Who are you? The Mysterious Stranger: An angel. Huck: What's your name? The Mysterious Stranger: Satan.
Is there a trope for when a synopsis/summary is misleading about what actually happens compared to what they say happens?