The Galaxy Brain meme, also known as 'Expanding Brain,' first appeared on Reddit in 2017 as a way to mock people who try to sound intellectually superior while proposing increasingly ridiculous ideas. Each panel shows a brain becoming more glowing and cosmic, representing a progression from a simple, logical thought to a completely nonsensical or meta concept. While it started with genuine comparisons, it quickly evolved into a vehicle for irony, where the final 'Galaxy Brain' stage is usually the most foolish or inefficient option possible.