3x11 - The Grim Adventures of Billy and Mandy

When Billy ruins his eyes by playing too many video games and looking directly into the Sun, Mandy and Grim suggest he see an ophthalmologist. When Billy refuses wearing glasses or having laser surgery, Grim uses his own scythe to zap his eyes. Although Billy has sharp and clean eyesight, he can also see glimpses of the future, specially horrific accidents that occur to his best friends. Grim zaps Billy's eyes multiple times to restore them to normal. Billy ends up with weird-looking eyes.