The story
From episode 28 of the anime TV series Dragon Ball Z ("The Return of Goku", 1997), referring to Goku's increase in power level. It should be noted that this phrase is a mistranslation from the first English dub produced by Funimation Productions and Saban Entertainment, whereas the line in the original Japanese script was 「8000以上だ！」IPA⁽ᵏᵉʸ⁾: /ha̠sːẽ̞ɴ iʑo̞ː da̠/ (lit. "Over eight thousand!"). Popularized by a 2006 YouTube Poop uploaded by user Kajetokun.
Etymology from Wiktionary, CC BY-SA 4.0.