Twin Sister's Cat Costume is a gadget in The Bigg House, found after completing all quests in the Den. It is a black cat costume for a little girl, consisting of a black shirt with a tail and a cat mask.
Once shrunk, Skitter can wear it. If he has it on, enemies, big or small, as well as the family members, will take no notice of him. This can come to your advantage when very low on health or you are entering a area high in enemies. Secondly, when wearing the suit, the family dog will begin to slowly follow you, allowing you to lead him to certain areas. The dog can take out enemies and interact with certain items in the environment. However, if you get too close to the dog, it will attack you with fatal blows. Finally, the costume can act as a suit of armor protecting from environmental hazards. Environmental hazards ment two restrict certain areas will not be protected against, however.