Fishing Rod

[Frogboy]

that idea isn't half bad actually, though it would be a bit difficult to set up by weight as treasure boxes have a weight of 1 (unless it has been changed), though in the script itself there could be a flag noting that it'll damage the rod, but there are a bit of factors to consider when doing this, though the most simplistic is to give the rod a weight limit that it can hold before breaking, and then give a % chance to break depending on how much heavier the item is compared to that weight limit, with the possibility of one or two items breaking the rod no matter what.

also a possibility is that you brought the fisherman the items already, so although he made you one rod, who's to say he didn't have left over material to construct new rods? for a price of course.