As you make your way deeper into the dungeon…
You arrive at an open doorway. Beyond it is an open square room that is approximately 30 feet across. However, looking up, you see that the room is extremely tall, so much so that you can’t even see the ceiling from where you stand.
Starting just before the doorway, where you are now, are metal tracks for a mine cart, bolted into the ground. They extend across the room before you, and through the next doorway. There is no mine cart that you can see, though.
The tracks within the room, and the ground around them, are all free of debris or any visible dirt - which is odd in a place like this.
How do you proceed?
There are a couple of ways to figure this room out, and more than a few ways to navigate it!
Figuring it out:
The extremely tall ceiling and lack of debris on the floor both point to one thing: A reverse gravity trap! The floor is clean as all dirt as fallen up. Likewise, the ceiling is tall so that an unsuspecting adventurer may tumble upwards to their demise.
The same conclusion could be reached by tossing a stone, coin, or anything else into the room before you. You’d catch on as the item soared upwards.
Solution:
The mine cart tracks on the ground can be used as monkey bars, allowing an adventurer to climb across the room’s “ceiling”.
Other solutions may include spells like Fly, Teleportation, Misty Step, Dimension Door, and so on.