Dud is a recurring ability in the Final Fantasy series. It is an undesirable ability as it causes various objects to fall on the player party's heads, inflicting damage. It is synonymous with the Gambler job class and is used whenever the player fails to match three of the same symbols in a row when using the Slots ability.
Dud is a small yellow bucket that drops on Zack's head that inflicts a small amount of damage and occasionally the Stun status as well. Dud may sometimes activate when the Digital Mind Wave enters Chocobo Mode and fails to match the symbols.
This can exploited if one of the girls has the accessory Cat Nip equipped. That girl will then deal 9,999 damage to the targeted enemy, which could be useful against bosses, especially if the girl equipped with it is a Gunner.