Amy Rose is a long-running character in Sega's Sonic the Hedgehog series, known as a cheerful pink hedgehog who knows Sonic well enough to spot a fake instantly. That familiarity is the joke behind this line, which circulates online as a short soundboard clip rather than a full cutscene. Fans reuse it in edits, streams and reaction posts whenever a character, cosplayer or player is pretending to be someone else, and its very short length makes it easy to drop into videos without interrupting the action.
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Amy Rose saying you're not Sonic is a short voice line from the games, used as a reaction sound for calling out imposters and mistaken identity online.
This is a brief Amy Rose voice clip where she calls out someone for not being Sonic, delivered in her bright, insistent tone before the line cuts off. The recognition is instant because the phrasing sounds both annoyed and disappointed, as if she has just realised the hero in front of her is an imposter. At under two seconds it lands as a quick punchline rather than a full scene, making the moment easy to recognise even without any video or context from the game it was taken from.