Piggybanks? I'm no psychic, but I've got the feeling that they contain something.
The Porkibank is a considerate companion and is always there when a Hoodlum needs him. In exchange for his services, the Hoodlums give him little gifts—In-game description, Rayman 3
Porkibanks, also known as pigpots or piggybanks, are destructible objects found in Rayman 3. They are very common and can be found in almost every level. Porkibanks are pig-shaped and -sized wooden boxes with a few metal platings, drawn-on eyes and mouths, and wooden pig-ears pointing out of their head. They belong to the Hoodlums, who apparently created them, and use them to store gems and red Lums. When porkibanks are first seen within the Fairy Council, Rayman must break them in order to magically open a door, prompting Murfy's sarcastic commentary on the contrived nature of the situation.
The previous design of the porkibanks.