Originally Posted by GameFaq

now tabuu is obviously a play on taboo, which is "forbidden". With that, he can be seen, besides a Tron reject, to be the parent of the child. Tabuu is saying that playtime is over, and proceeds to take away the child's toys. the Child obviously does not want to give it up and fights back but is later subdued (chained by tabuu) and is forced to go along as the parent repossesses each toy