The expanding brain meme began circulating online in 2017, using a sequence of increasingly glowing brain images to rank ideas from ordinary to supposedly transcendent. The galaxy brain version pushed that joke further, replacing the final brain with a glowing, cosmic image to suggest an idea so advanced it had left normal thought behind. As the format moved from image boards to short video platforms, creators added swelling, space-themed audio to match the visual escalation. It remains popular because the structure is instantly readable, endlessly reusable and perfect for ironic praise.