My story takes place in an archipelagus in world X, inhabited by people X.
In the shores of the capital city of that archipelagus, there is a bay of deep, dark waters. It's supposed to be dark and deep enough to feel scary and lovecraftian.
From that bay, people Y simply float up from the darkness, naked, and unconscious in a coma-like state, and are then literally fished with fishing nets and revived by a permanent patrol of glorified elite lifeguards, and are integrated into society X.
Upon being revived, people Y have little or no memory of who they are or where they came from but, those who do, all have the same memory: They came from world Y, and that's all the memory they have, most of the time.
Basically, the darkwater bay is a portal between world X and Y that no one remembers crossing. (There actually is much more to it but it's not exactly relevant to this question)
Most of the story revolves around the relationships between people X and Y, their power dynamics, prejudice, and cultural differences. I will most likely come back here for more questions but my question for today is: How can people Y be visually identified? (Both X and Y are regular humans)
I tought, at first, of some sort of scar from the salt water or sunburns from floating in the sea, or maybe marks from the fishing net (I intend on working on an insult from people X to people Y that compares them to fishes or something), but I'm not sure that's even possible.
How can the experience of floating in the sea (forgot to mention it's a tropical and sunny place) and then being fished by fishing nets physically mark people permanently?
(edit: Another idea I came up while writing this: Since I'm going for a lovecraftian feel, maybe jellyfish scars might be good, because they have tentacles and can somehow inject a toxin that might work as a plot device (such as, the toxin makes them not drown or something), and eventually, some special characters might have specially large scars, that somehow makes everyone go "OH MY GOD THAT SCAR IS SO BIG IT MUST NOT BE A REGULAR JELLYFISH BUT SOME MONSTER FROM THE DEPTHS!", which could work as an "imminent disaster" plot device. I google "jellyfish scars" and they definitely look like something out of lovecraft. Any opinions on jellyfish?)