This was kind of put off for a couple of days, but I had this dream twice.
I'm traveling through these underground industrial ruins, searching massive, dark, rusted tunnels for signs of living civilization in a colossal, inescapable complex. I eventually stumbled upon this large, rocky passage that leads to a small makeshift gate put together out of a couple of sheets of rusted copper, and a thick fence made from a bunch of sticks of wood. The gate was open, so I entered.
It leads to an absolutely unfathomably large old railway tunnel. The walls are entirely covered with rust, and so is almost everything in there. There are houses all along the walls of the tunnel, and an entire city of people living there, off of the remains of an old time.
I talk to the people, and live with them. They tell me that a monster nearly the size of the tunnel is going to come to destroy the civilization, and they ask my assistance in helping to defend them, and myself, from the approaching beast.
I was clueless at first, but I somehow managed to get the people to help me create a huge cage, made from a very dense bar sort of metal, a bit like chicken wire, but rectangular, and extremely strong.
When the monster came, it wildly burst through the entrance from which I came, charging rapidly, not paying attention to anything. I don't remember how, but we ended up luring it through a round glass tunnel opposite the entrance gate, which turned 180°, rose, and led into the cage, where the destroyer was trapped, thrashing at the walls. We were mites in comparison.
That's as far as my memory of the dream goes.
While I'm at it, I'll add another dream that I just remembered. I don't know how long ago this was, but it was at least a month.
I was playing with a bunch of friends in this big structure made of plastic, and there were playground slides coming from all ends. I only remember one sort of wing coming off the main structure. There was a ramp or something leading up, but it wasn't too tall, just about the height of regular playground slides. The interior of the section was just too short to walk, so I had to crawl. There were two or three slides right next to each other coming off three sides, and a tunnel leading to the rest of the structure on the side opposite the entrance.
I kept going out the slides to the left of the entrance. The surrounding area went on for a few hundred feet, or maybe yards, and then appeared to close off on all sides with walls. I don't know if they were walls or just a trick, and the sky was the same color as the ground. Everything was green; the structure, the ground, everything. The ground was a foam, like those floors some people have for their kids. Somehow, the place reminds me of Happy Town from LSD: Dream Emulator. It must have had a similar atmosphere somehow.
The weird thing, though, was that everyone was like a Whinny the Pooh character or something. Not like a real character, but those suits that they wear at amusement parks when people dress as children's characters. And we were just playing. I don't remember any dialogue. It's just a very faint memory, but I feel like I may have had it multiple times, maybe recently.