A difficult platforming challenge that brings the bearer great pain until they manage to beat it. Then it feels gooooooood

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

The hardest difficulty of levels in the game Geometry Dash, which is easier than only Impossible. These levels can take thousands of attempts for the most skilled players. These levels involve straight flying or flying through tight spaces, frame-perfect timings, stretched triple spikes, or sometimes level obfuscation or memorization. Sometimes, high framerate monitors are needed to complete these.