What is the definition of Classified Studies?

Classified studies, folks, are like the secret recipe for a super-sneaky spy novel. They're research projects that are shrouded in mystery, wrapped in secrecy, and often involve things you'd rather not know - like what kind of superheroes are secretly plotting world domination, or if aliens are just messing with us over coffee.

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Here's a particularly unsettling example sentence: "The classified studies on the effects of caffeine on human behavior revealed that deep sleep deprivation makes you think more like a grumpy cat."