Hidden Block Alert

The Hidden Block Alert is an accessory in Paper Mario: The Origami King. It takes on the appearance of a small handbell, painted entirely gold and marked with an olive green icon of a ? Block. Mario can purchase this accessory in Snif City, and when equipped, it will automatically ring whenever he enters the general vicinity of a ? Block that he hasn't hit yet, whether it's hidden or in plain sight.

Unlike other accessories, whose upgrades are also in accessory form, this one can be replaced by the Hidden Block Unhider, built by the Sensor Lab Toad and unlocked after a certain point in the game.