Haman wasn't the only character in the Bible who got executed by impalement, or even the only one in the book of Esther. However, he stands out for both scale and irony. Fifty cubits is about 75 feet long, instead of a more utilitarian, manageable length like what they typically used to impale people (by the way, you probably don't want to click that link).
We've done our best to tastefully represent the impalement process here.
We have previously mentioned the story of Haman and Mordecai -- basically, Haman was the Hitler of ancient Persia, but his plan involved fewer blitzkriegs and many more giant spikes. His attempt to slaughter all of the Jews took an unexpected nosedive when King Xerxes fell in love with a Jewish woman and Haman found himself hoisted by his own petard, where by "hoisted" we mean "impaled" and by "petard" we mean "75-foot spike." We can only assume Haman's body slowly corkscrewed down to the bottom, just like in the Jason X clip above.
What's important is that he died doing what he loved: being a bastard.