The line comes from Baby Got Back, the 1992 hit by Sir Mix-a-Lot built around the opening declaration I like big butts and I cannot lie. Theodore Seville is the sweet, food loving youngest member of Alvin and the Chipmunks, a cartoon group created in 1958. Putting that lyric in Theodore's squeaky voice became a shareable online joke because the pairing feels completely mismatched. Clips and edits kept circulating on soundboards and social video, where short familiar hooks work well as instant comic cues for dances, entrances and throwback nineties humour.