Pluto, the dwarf planet

With Malcolm's interest about space the topic of Pluto came up.  Pluto was demoted in 2006 to a dwarf planet due to its small size and erratic orbit.  We jokingly told Malcolm that he was just like Pluto, because he can not walk a straight line similar to the erratic orbit.  He did not like the comparison,  and gets very upset when we mention it, but it cracks Ashley and I up every time.