"That's Arfur. He's always hanging around here. He looks totally suspicious, but apparently he lives by some super-stern moral code."
It should also be noted that Swindle's tattle also mentions Arfur:
"That's Swindell, the bandit. At least, I HEAR he's a thief, but I've never seen him steal. He's always whispering to Arfur about something."
Arfur has a trouble that involves Mario going to the shop and seeing how much three items, including Fire Flower (10 Coins), Sleepy Sheep (8 Coins), and a Tasty Tonic (3 Coins) cost. Once you return and give the correct price, Arfur will reward the player with 20 Coins. The name of the trouble is Price Adjustment.