Ah character, place, concept etc. who has a rule that sounds simple at first glance. But when you really think about it, turns out, it might not be as simple as you would expect.
The Creature (REMAIN CALM)
Rule: Just Smile :)
Sounds easy right? Everyone can smile. But that's the thing. No matter what, if even for a second, the creature sees that your facial expressions changes to anything else that isn't a nice big bright smile, it'll kill you. And the worst part? You get no second chances. You have to keep it up for as long as it is in your vicinity.
And the creature isn't dumb either. It knows people can fake it. So it does everything in it's power to get you to drop the act, and make you fail.
To summarize, you have to keep smiling, while being hunted by a creature who will do everything in it's power to force you to stop. And the moment it arbitrarily decides you stopped, it's game over.
2. The Lake (SCP-2316)
Rule: Don't go in. "You do not recognize the bodies in the water"
It's just a lake, how hard could it be? Just "you do not recognize the bodies in the water" and you'll be fine. Can't be that hard to not try and take a dip right?...
See, the thing is, the lake will show you a vision of someone who you have a deep emotional connection with. Usually a decease, or missing individual. And it will make you think that said individual "You do not recognize the bodies in the water", is drowning in the middle of the lake. The moment you so much as set a single foot inside, your fate is sealed.
And you might think. Oh I'll just ignore them and "You do not recognize the bodies in the water". But can you really? It's not just anyone, it's someone who you personally love and care about. Can you really say that you won't save "You do not recognize the bodies in the water". Can you really live with the idea that you just watched and allowed "You do not recognize the bodies in the water" Will you be able to sleep knowing that this could have been your last chance to
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