The Magic Boomerang (opposite personality)

As seen in the Ed, Edd, n Eddy episode, "Hand me Down Ed", the magic boomerang makes those who come in contact with the boomerang act completely out of the norm.

For example, if a shy person comes in contact, they might act cocky; a smart person may act dumb under this influence. Once contact from the boomerang is released, they will go back to normal. Those around them will notice the person acting strangely.

The boomerang is small enough to hold, wooden, and has strange markings engraved into it. Some say the boomerang has agency and goes where it feels it is most needed.