I received another email recently about a cat who became stuck in the wall in HM DS. This is an unfortunate situation that can occur randomly and when it does, it usually spells eternal imprisonment for the poor creature, like the cat in Edgar Allan Poe's famous tale.
While responding to the player, however, a possible 'fix' occurred to me. It only would be possible if you have not ordered all expansions from Gotz yet.
Whenever you order a house expansion from Gotz in HM DS or Cute DS, your Dog and Cat, if inside the house at the time, are at risk of being imprisoned in the new walls. I do not know WHY Gotz fails to notice them, but he sometimes is guilty of this oversight.
So my possible fix is: order ANOTHER House Expansion from Gotz. When the walls change again, your Cat or Dog MAY be freed from the unfortunate imprisonment. Note that I use the conditional word 'may' here. Even so, a possible fix is better than none, and I would be thrilled to hear from any player who tried this and succeeded in regaining his/her beloved Pet!
As previously stated, it only becomes an option if you did not order every expansion previously. Fortunately, there are many possible expansions in HM DS and Cute DS, including Bathroom, Restroom and three Basements...