Eris is a planetary destination in the 12Fold Resorts.
From the Visitor's Guide
Eris is so far out there, and she's had so many reality-hacking experiments performed on her, and so many were deemed failures. But Eris still became such a happy place, liberated from the burdens of consequence or permanence. Her visitors and residents are merely figments of each others' imaginations, prone to dream one another into eight-armed lizard gods made of tiny train tracks, or fields of colorful electric ducks. They are often distinguishable from the terrain only by arbitrary tradition, since the local geometry operates under the postulatum of Metron Ariston; it's not unusual to see, say, a lion and a mountain engaged in orgiastic partner-swapping with a bacteriophage and a large prime number.
The natives shed and acquire new bodies and personalities so quickly, they don't bother trying to name or identify discrete individuals. Instead, they speak of a few basic archetypes and their infinite combinations. Whatever mask you're wearing, that's who you are. Speaking of a personal history is considered quaint at best, and given the already unpredictable nature of Erisians, probably best avoided altogether. This gets easier with time, as personal memories fade; a few days on a saner planet will usually restore visitors to their old selfhood, though typically the longer one stays, the less comfortable the return to ego will feel.