This monster appears as a physically large Jar with a smilling face engraved into it. It has a large nose, two wide open eyes and gleaming teeth prominent to its face. The handles resembles ears and the cover looks like a hat.
Lucky Jar cannot be hurt by conventional means, and so do not attack with conventional methods or use dragoon transformations. Unless you use Miranda and equip her with Virulent Arrow which can inflict Poison upon a target with a given probability, then you should use Poison Needles which can be obtained at Ulara for 20 Gold. If you have any Sachets stored within your inventory, they will instantly eliminate this monster since it will always deal 10 damage. This is the best method, however, they are very limited and very rare to obtain by fighting which leads to it not being worth grinding Piggies for in Home of Gigantos.
Upon defeat, this monster will drop the item Moon Serenade without fail. This is a great item and you may want to battle these to obtain several, maybe. They take on average roughly 5 minutes to obtain if you followed the above recommendations from the battle tab.