My son has a superhero costume that comes with a cape attached to the shirt by velcro. The cape has four corners and is cotton. Is the cape obligated to have tsitis?
No, this is not worn for the purpose of a garment, i.e. for protection from the elements. Rather it is for costume play, and hence not considered a arment with regards to the obligation of tzitzis.
Orach Chaim SIman10, Biur Halacha s”v Sudar.