Heart of gold
A heart of gold is a random artifact found in Godville. A heart of gold has no use to heroes, but can be sold to a merchant for a high price. Gold is expensive, so most monsters can only afford a small heart. Either that, or the monsters are only capable of possessing a small heart due to their nature of, well, you know, evil. This means that the monster is mean, but this gets contradicted by the heart being made of gold, so the monster is actually average. One particular pun about this artifact is: Man 1: "you have a heart of gold. Hard and yellow." Man 2: "no I don't, I sold it to the trader." Man 1: "that's a rubbish pun. Sorry for wasting your time."