Falkir’s Helm of Pigheadedness
Other, unknown (magic)
This steel helm is shaped like the head of a boar. Once you don the helm, it can’t be removed until you die or until a remove curse spell or similar magic is cast on it. If you wear the helm and are a humanoid, you gain the following flaw until the helm is removed: “I’m exceedingly stubborn and think I’m right all the time.” (This flaw supersedes any conflicting flaw.)
Source: Waterdeep: Dungeon of the Mad Mage p. 141