This line comes from Dragon Ball Z, where Vegeta uses a scouter to measure Goku's fighting power during the Saiyan Saga and is stunned when the reading climbs past nine thousand. The moment was lifted from the anime and turned into one of the internet's earliest viral reaction memes, remixed in countless videos, edits and jokes about power, size and exaggeration. It has lasted because the delivery is so intense and the number so specific that it instantly signals something far beyond normal limits.