The Curse of Monkey Island/Nightmare Fuel

• The consequences of mixing the drinks in order to (almost) kill Guybrush were downright terrifying for kids playing back in the day.
• Looking through the crack in the Goodsoup family crypt and popping up behind the stump in The Secret of Monkey Island's Mêlée Forest, while a horribly fucked up version of the original music plays was very disturbing.
• The super-secret Easter Egg where you end up under Secret-style Mêlée Dock, the same horrible music plays, and Guybrush casually comments on his own dead corpse is the worst.
• LeChuck's resurrection on the pirate ship, and the pirate screaming at the sight.