Boomerang Pet Ball
The Boomerang Pet Ball is a toy that SpongeBob bought for Gary in the episode Gary Takes a Bath. It made its only appearance in that episode.
Design on the box
The box label says, "New Boomerang Pet Ball. Really Works". It is a small box that just fits the ball.
What it does
As the name suggests, the ball is a boomerang. It can be thrown, and returns to whoever threw it.