Sakupen Circles is an Extreme Demon level in Geometry Dash created by Sakupen, inspired by the earlier Nine Circles wave levels and by Sakupen Hell. Its cramped, fast wave parts made it famous as one of the game's hardest challenges for years, and clips of attempts, completions and reactions spread widely through YouTube and streaming communities. The level's music became shorthand online for extreme difficulty, so creators reuse this section in edits, memes and montages even outside Geometry Dash to signal a challenge that looks almost impossible.