Imagine blissfully walking around with no care in the world. Out of nowhere, you get hooked and get caught in an electric explosion. The next thing you know, you're dead.
Welcome to the Blitzcrank Special, a build that will make your adc and enemies mald. Your hook and ult combo will one-shot, and your ult will be available almost instantly late game. If you don't instantly kill your target, your knock-up will buy your teammates enough time to finish them off. Although you won't be tanky anymore and will probably be victim to being one-shot yourself, Blitzcrank was always meant for picks anyways.