...on B1257+12 C

Where the "beach" is just a steep cliff to lower elevations (on the order of miles and miles) where the atmospheric pressure is so high that the gasses comprising the air itself are forced into liquid states and form layers like a compound ocean (or "sea-ception" if you must).
Nachtan like Cheddar can actually swim in the water layer of this sea, since it is probably where hydrodynamic-based organisms first evolved. But it is not advisable for anyone of any other biochemistry to attempt this swim, since the extreme atmospheric pressure just above the surface of the top water layer tends to make it a balmy 1000 degrees celsius, as opposed to the relatively habitable 8 degrees C way up inland where Nachtan civilization happens to be located, fortunately for everyone.

Another side effect of this is that the extreme pressure and temperature gradient makes it nearly impossible to directly see the sea undistorted from the top of the "beach". Optical lensing, ducting and attenuation by ultra-dense haze wreaks havoc on the vistas long before they reach any sight-seers ashore. Still, it is a great place to see extreme forms of mirages that on Earth had historically been the subject of wonder and mythological inspiration. For instance, the Fata Morgana is so extreme here that it resembles a monochrome Aurorae Borealis.

I really don't know what Cheddar is doing. Probably picking out a rock to throw at the sea - which will probably burn up before it gets to the water, so it's not like the sea would care, not that it could anyway. Or maybe he's taking a hike and is miffed about it. I don't know.

(5.5 hours, Photoshop)