The line comes from Jimmy Neutron, the boy-genius hero of Nickelodeon's Jimmy Neutron: Boy Genius, whose shouted Brain Blast marks the instant an idea strikes him. The show began as a film in 2001 and ran as a series from 2002, making Jimmy the defining cartoon genius of his era alongside Dexter of Dexter's Laboratory. Short clips of the Brain Blast moment spread across meme pages and soundboards, where this particular upload by AquaticNeptune found its audience. Editors keep reaching for it because the panic of a brain refusing to work is universally funny.