This item itself is used by one to use a Chain Chomp to attack a random target to steal coins or stars from (depending if the target has a star). When the orb is used, the player throws a bone and the Chain Chomp pursues it when the bone falls off the edge and steals coins or stars by any attack opponent in the process.
In Mario Party 6, the effects are identical, except that the game renamed the item to Snack Orb and is found only on the boards Snowflake Lake and Pyramid Park (where Chain Chomps are known to steal stars on these boards). In Mario Party 7, this item isn't used on opponents, but rather protects the player for three turns from attacks, Red Spaces and such. Or, more uncommonly, it protects the player from a Chain Chomp attack.