//------------------------------//
// Machinations 
// Story: Book 1 - The Behemoth came to Canterlot 
// by Equimorto 
//------------------------------//

It was clearly a puzzle of some sort. He could see the door, hidden behind the crumbled rock. He just needed to figure out how to get it to open. An ordinary pony might have assumed the entrance had crumbled, but not him. He could see clearly that it was not the case there. It was a puzzle.
He sat down, contemplating the vaguely skull-shaped rock formation and the swamp around it. It looked a bit like a swamp at least. He wasn't sure, he hadn't been paying attention when he'd gotten there. He wasn't even exactly sure where he was or how he'd gotten there. But he wasn't crazy. He'd just been a bit distracted. And there was a puzzle there for him to solve.
It wasn't too complicated, he was sure. Not if he looked at it from the right angle. Now, the other entrance on the other side, that one was legitimately unusable. But the one in front of him could be opened. He was sure of it. Very sure of it, he could feel it. He was good at puzzles.
And there was that small chunk of rock, there to the right, a little above his height but not too far. He could reach it. It could be pressed, or pulled or maybe twisted. It was clear, the way the base stood out against the wall made it clear, it was almost outlined. But it couldn't be so easy, could it? He looked better.
There was a switch of some kind. Yes, he could see the connections from that button. It could go to the door, there was a path there, but currently it was pointing upwards. A separate wire, leading somewhere above. A trap, most likely. But a switch was there, to redirect the path, and he just needed to look around for it.
There. There on the ground, to the left. A pressure pad, half hidden behind a chunk of broken rock. And he could see the connection, the wires leading from it to the switch near the other button, embedded inside the rock wall, faintly shimmering as ghostly apparitions to his eyes. Extending one hoof, he pushed down on the pressure pad. The switch rotated, redirecting the first wire's signal, and he reached out with his front hoof to push down the button.
There was a click. The ground shook, just a bit, and as he drew back he saw the previously crumbled entrance open up. A few chunks of broken stone fell down, while other sections of the wall slid out of the way, and a moment later the passage was free of hindrances and everything went still again. He felt rather proud of finally having solved a puzzle. He'd told them he wasn't crazy. 
A broad smile on his face, he stepped into the cave. It was mostly orange, filled with sharp rocks, and after a moment he realised he wasn't exactly sure why he was there. He did however notice a purple alicorn was also present, and was staring at him with a confused expression.