to forcibly expose a person to an idea or lesson that leaves he or she, dazed and awestruck, to go through a bout of depression that lasts a variable amount of time in which they question existence, religion, and what they themselves would do in hypothetical situations. Usually the said person will ponder these questions at all hours of the night because they can not sleep and will end up finding only a few answers/revelations. Once of which may include that "if" is the most evil word in the English language. Eventually he or she recovers & usually feels a mixture of a hate & love toward the mind-fucker. Hate for their mental/emotional anguish and love for the perspective they gained and the lesson they learned.
Dude, I totally got mind-fucked by one of Ellen Hopkins books the other day.