2. Luis (Grand Theft Auto IV: The Ballad of Gay Tony)
It was never a real smart move to have Niko Bellic drink - his vision got blurry, steering a car became near impossible, and you couldn't even draw your weapon to mow down innocent bystanders with. Really, it's the best anti-drunk driving campaign the entertainment world ever thought of - it shows you how much it would suck to drive drunk in a way kids can immediately relate to.
The Ballad of Gay Tony took things a step further - no longer could you only drink with friends or dates. Luis - the main character of the DLC - could drink alone, and when he did, he would often blackout, and wind up in some bad spots, including fountains, ships, dumpsters, and worst of all - mid-air, plummeting towards the ground (thankfully, with a parachute on). Parents who worry about all the bad lessons GTA teaches kids, remember this: kids may now think drinking alcohol leads to blackout skydiving. If that doesn't scare 'em sober, nothing will.
1. The King of All Cosmos (Katamari Damacy)
To keep it simple: The King of All Cosmos, the king of the known galaxy (or something), the Prince's dad, and prominent-bulge-displayer, got suuuper-wasted one night and destroyed all of the stars in the sky. That's right - forget entropy, forget nuclear fusion - because all it takes to get rid of the primary source of power and energy for the entire universe is one drunk space giant with bad fashion sense. No matter how bad of a night you had after waking up hungover, no matter how many hijinx you've gotten into with Ed Helms and Bradley Cooper, nothing compares to essentially destroying the universe. And to add insult to injury, the King doesn't even have the decency to fix the problem himself - he has his tiny, ball-rolling son do all the dirty work of gathering materials to re-make the stars. And to make matters insanely worse, the "materials" are "everything on Earth, including buildings, animals, mountains, and human beings themselves."
When one bad night of drinking leads to the destruction of Earth, maybe you should consider switching to something less dangerous. Hell, even people on crystal meth don't get that wild.