Which I can’t really describe well unless you’ve welded with one on, but I think it looks like a green-blue electric storm….frozen in time.
LoCaS is my mind has no light source aside from perhaps a moon that the planet floats in some proximity to? But once you enter any of the cave tunnels, the only light comes from the water that has crazy high amounts of bioluminescence floating by, or inexplicable electric pulses surging through, or both.
The water itself is absolutely pure- a complex system of freshwater springs and whirlpools all connected to an abundant aquifer LoCaS’s cave system barely scrapes, even at the deepest depths. Within these caves are various metal deposits that can be captchalogued and alchemized (what would be more useful to Equius???), stalactites and other dripstones that often bar the way through the tunnels.
Much of LoCas’s challenge, despite “posing no challenge” for Equius at all, is adventuring through the underground systems, often reaching dead ends with no rewards, and paying mind to not use brute strength to forcibly navigate the caves: this risks cave-ins and great personal injury. I imagine that Equius got fed up very early on with the ~mysterious~ nature of his planet’s terrain, forgoing any treasure hunts or puzzle challenge elements in order to leave LoCaS and get to Aradia as quick as possible.
I also believe that the further one travels into the underground systems, the more alone you are with you and your thoughts- private introspection literally echoing off the cave’s interior as the aquifer draws near. The pressure to stay calm and collected while navigating the caves that promise some ambiguous arcane knowledge…mixed with the land’s dreary topography….the panic that comes with treading water under an air pocket as you fight madly to find your way through the darkness, suffocation imminent, situations where strength does’t help you.
That sense depriving mechanism of the auto-darkening mask, wherein perception of space dissolves into the peripheral void, like a horse with blinders on. You rely solely on muscle memory. The only thing you can see is the green glow of the torch illuminating the aluminum as it chromes and quakes and cools.
SO YEAH, LoCaS SOUNDS FUN