First, InfernalNightmare333 (I’ll just use “Infernal” from here on out) spells out procedures and items needed to perform a ritual, which must always be conducted in an empty church at the stroke of Midnight. The materials include salt, red or white candles, red string or thread, and a full-length mirror; all electronic or mechanical devices are expressly forbidden and must not be kept anywhere near the ritual location, and no religious symbols can be worn on your body.
Infernal then instructs you to pour salt around the mirror to create an unbroken circle, then wrap the mirror several times with the red string. The candles are then to be spaced outside the circle at even intervals, and lit in clockwise order. Once these protections are in place, you must then perform some sort of blasphemous or sacriligeous act within the church (it could be as simple as inverting a crucifix) before shutting all entrances and extinguishing all lights apart from the candles.
Then it’s only a matter of staring into the mirror and wishing intently for the Devil to appear. When you have fully concentrated on this wish, close your eyes for ten seconds and then open them again… at which time (theoretically) you will no longer see your own reflection… but Satan’s own eyes staring back at you.
That’s the easy part. Assuming everything goes as planned, Infernal then says it’s time to challenge Lucifer to a game of “question-and-response.” The Devil will then initiate (he always goes first) by asking you a question, which may come as a riddle or a request, perhaps about something intimate and personal. When this is correctly answered to his satisfaction (the criteria for “correctness” is apparently unknown to anyone but him), he will then presumably provide an honest answer to any question you pose to him. However, if he is not satisfied with your answer, He is given license to lie to you at some point in the Q&A process… and you’ll never know which of his answers is the false one.
While Infernal claims that no dire consequences have resulted from wrong answers, any attempt to break off the game without the Devil’s consent will have very unpleasant results… and you absolutely must finish the game before 66 minutes and 6 seconds have elapsed, or your soul will be forever trapped in the mirror. Also, no matter what you hear or feel behind you, you must never break eye contact with the Devil’s image — doing so will release him into the room with you. Finally, if the Devil asks you at any point to tell him your full name… DON’T.
Throughout the course of his instructions, Infernal describes several diabolical scenarios that may result if one fails to follow the rules. None of them are certain; they’re just hypothetical… but he also ensures us that none of these imagined outcomes will probably compare in pure horror to your own personal experience if you play the game wrong.
Needless to say, Infernal’s post generated a great deal of controversy (especially in the wake of the so-called “Slender Man stabbings,” to the extent that he had to issue a disclaimer assuring readers the game is completely made up… but that doesn’t keep him from warning you never to play it.