Elias has a book that has a page that shows a kangaroo hopping, and the caption is "Hop, hop, hop!" So one day after reading that book with Elias, Justin decided to hop around on his knees like a kangaroo. Elias thought it was HILARIOUS! Justin took a video while hopping, so it's pretty bouncy and blurry, but you can still get the idea of the hilarity. You can see Elias bouncing along with Daddy, and he keeps doing a high-pitched grunt and shaking his head, which means "Do it again, Dad!"