Even though Henrietta and X supposedly left their shadows at King Friday's castle, if you look carefully as Robert Troll is returning them, X and Henrietta are already casting shadows on their doors!
If you look carefully in this same scene, as Robert Troll is holding up X's shadow to show X, it's casting a shadow of it's own! Since when can shadows cast shadows?!
This was the last visit to Someplace Else and, in addition, the last time the show saw Harriet Elizabeth Cow or Donkey Hodie.