The Leopard Skin Pouch is a magical pouch made of leopard skin that is used by immortal warriors to hold any number of objects, such as weapons and armour, magical items, and even powerful beasts. The bag is small and can be carried on one's side, the reason it can fit so much inside is because the items shrink as they enter the pouch.
In the story of Ne Zha (哪吒 né zhā), Ne Zha was bestowed a Leopard Skin Pouch by his master, Tai Yi Zhen Ren (太乙真人 tài yǐ zhēn rén) to hold his multiple magical weapons and items.