This will most likely be the first special encounter you come across. A robed figure guards a bridge that just so happens to be the only path to the map's exit. In order to pass by him, you must first answer three questions dealing with the game's skills, perks, or statistics.

Answering any of the questions incorrectly gets you killed, so you'll want to save before attempting to pass by. If you retaliate with your own question on the third attempt, the guard will die and you're free to loot his Bridgekeeper's Robes and cross over the chasm. If you'd rather not deal with the questions, you can always attack the robed figure... but you better be prepared for a massive fight. In addition to being extremely powerful by himself, the bridge guardian will summon exploding Brahmin. Should you beat him, you'll earn 7500 experience points and can cross without the bridge any other issues.