Set dressing when describing locations to players can lead to atmosphere, veracity, and immersion in the fiction.
It can also lead to players obsessing over tiny details that are only there to look cool and have no real relevance beyond that.
But the smart GM can lean into this. Some things need to be significant and important. And often players will overlook or not find the important stuff. But allow them a certain slipperiness, and the mundane broom in the corner that was simply there because you decided the monsters need to clean occasionally can become the Mystical Broom of Righteousness, replacing the Sceptre of Righteousness that they overlooked three rooms earlier.
Commentary by memnarch (who has not seen the movie)
Aaaaaaand back to Rey. Who is now in a large body of water. That's better than going splat onto a hard surface of some kind at least; no guarantee aside from plot that there wouldn't be something safe to land on after getting pulled in. If the area above the water's surface isn't slimy looking like the opening however, I'm going to be disappointed, I think.
I guess that's dragon-like. I think it looks more like an alligator skull myself, but that might just be the "currently underwater" part of the skull. Dragons do be more interesting on the fantasy side than alligators in general, and there are also a lot more varieties of shapes that can be called "dragons" than alligators have. And in spite of the inconsequentialness of the skull, knowing if it's been disturbed would be good to find out here in case of hungry predators. It's just, you know, a bit less important to find out at the moment. The "Dark Side", or whatever it is down here, probably doesn't purposefully kill by lack of oxygen. Probably.
Transcript
GM: Let’s leave Finn to ponder those... words of wisdom.
[SFX]: Splash!
GM: Rey plummets 20 metres or so and plunges into an underground pool. You see a dragon-like skull on the bottom.
Rey: I use the underwater oxygen extraction apparatus.
GM: You gave that to Luke, remember?
Rey: Damn.
Rey: I examine the skull.
GM: It’s just a skull.
Rey: Aha! It must be important. I inspect it more carefully, looking for any unusual markings or erosion.
GM: You’re still holding your breath.
Rey: Good. I didn’t want to inhale water.
GM: I mean: You better surface soon.
Rey: Why do you obsess over inconsequential things?
Rey: Does the skull have any teeth marks on it?