Thanks dude, ngl its a very good prompt.

Two men are standing infront of the door, in yellow labcoats, notebooks by their side and a pen inside their pockets. It is silent, dead silent. They stare at the door and onto its lock, the dull, mundane colours of the empty room surrounding them engulfing them. One of them checks his wristwatch.

'It's been quite a bit above average. Should we sent somebody in?' he says, putting his hand back behind him where it was, his eyes not leaving the sight of the door.

'He'll get out. Trust me' says the other man, slightly older with small round glasses and an elegant white beard.

The two wait, the first one goes front and takes his hand up as to knock the door

'Not yet' says the other man motioning at him to step back.

They sit back and wait, a drop of sweat falls down the face of the first man. He quickly brushes it off.

'Now James, it's not the first time you're doing this.' says the second man.

'Yes... Yes Dr. Comb. Indeed.' says James, visibly stressed out.

'And how did it go the other times?' says Comb, trying to comfort him.

'They all came back. Sir.'

'Good. And it will happen again, you can go if you want, get a cup of tea and calm down.'

The sound of the door unlocking interrupts them, a man comes running out, he pushes and locks immediately, he has visible scars and bruises on him. 'I'll give my report later.' he says, as he sits against the wall and tilts his hair back in relief.

'See I told you' says Comb, now looking at James.

'Told him what?' shouts the man that came out of the door, 'That there were gonna be giant squid monsters on the other side? What the fuck kind of key even was that?'

'One from the lovecraft collection' says Comb, he pauses a bit 'Now lets get you somewhere safe and warm' he continues, wrapping a blanket around the man and escorting him to a different room.

This thing was found about 30 years ago, we were lucky enough for no government to try to get their hands on it, well, lucky enough to manage to hide it from them. God knows what they would do with this power. It can be the most mundane normal room at the other side of it. Practically a portal to whatever room the key would normally open the door to would lead. But some keys are special. First of all some lead to places that have no other visible entry or exit except for the purple door, those places appear to only exist through the door and can be mundane rooms, or things a bit more surreal. Broken keys can lead to fractured versions of the world. No person has so far been seen in these worlds, but other things, monsters, are found frequently. Very rarely a sentient one is found and the few times those were found they were either unintelligible or incredibly sociopathic. All have refused to exit the door with all means that are available to them. Some have even preferred death to exiting.

Science cant make sense of it, religion surely cant make sense of it, no mention of it in any text, historic or otherwise. This is the real Stonehenge, or worse, the things it implies. This thing implies that we do not understand the universe, the places it has lead to nullify or simply ignore the laws of physics, sometimes all at once, almost as if to mock us. This thing is here to prove to us, remind us, that the universe is untameable, unsolvable. But we run tests on it anyway, we travel through it everyday in hopes of making some sense, of finding some reason. I don't believe we will. But atleast its fun trying.