Outer Wilds spoiler alert!
I really like the Hourglass Twins concept, and I think it could fit in interestingly in Lethal Company.
There should be two binary planets that are interconnected with each other. One of them is made of red stone, and the other is covered with sand. A ship arrives on a planet made of stone, and there is a cool gameplay feature for this planet, while another planet will act more like a big decoration in the sky.
Main feature of this moon will be that over time the sand from the sand planet is gradually being poured onto the planet on which you landed, and this sand is going to closing various places, passages, but adding new ones.
Without sand, it will be impossible to get to one fire exit, for example, however, if the sand floods the fire exit, then you will not be able to get out of it. There may be some tunnel-like passages that eventually fill up with sand, and it will no longer be possible to get into them.