No, these weren't golf-ball-sized potatoes. They were some kind of local fruit called langsat, and it was apparently in season right now. I thus tried one; it was kinda like a lychee, but the white flesh inside is in segments like a mangosteen. The taste was mild just like its two brethren, but those little bitter seeds in each segment made it a bit of a challenge. Like eating sunflower seeds, you need patience to eat these things.