pull a cousin oliver

when a TV show adds another younger character because the previous younger character(s) on that show has become too old and outgrown their cuteness.

Term originates from when The Brady Bunch introduced a new character named cousin oliver (in what turned out to be the final six episodes of the show) because all the cute kids grew up.

when raven - symone was added to the cast of the Cosby Show because Bill thought Keisha outgrew her cuteness

pull a cousin oliver example numer dos: Malcolm in the middle, when Lois got pregnant around the 4th season.