Known in "classic" Baldur's Gate as Marl the Drunk, this is a chance to win a significant experience reward. Marl is an agressive drunk found in Feldepost's Inn. Depending on how you speak to him, he will most probably begin attacking you. If you choose the moral high ground and talk him out of a fight, you are rewarded 900 xp. To calm him down, choose dialog options 1, 1, 3, 3, 1. Alternatively, when he attacks you can use a spell or ability such as Charm Person to pacify him. If you kill Marl after you have calmed him down, you will lose Reputation.