This reminds me of man's relationship with dogs.
A dog can help man over the biggest emotional hurdles. A dog can run circles around man and leave them in the dust but they choose to stay because man and dog have a symbiotic relationship even though they are vastly different.
One might think that the ball is doing everything for the cube but as you can see in the reaction from the ball when the cube comes upstairs the ball is ecstatic and receives joy from the company of the cube who might can assist in other ways as well.
The biggest difference is that the cube has no arms to rub peanut-butter on his balls and I don't think the red ball has a tongue.