Wondrous Item, Rare
This bag is exactly like a bag of holding, except the bag has gained a small measure of sentience. Anytime you try to interact with the bag, it will have something to say about it. Like a token Jewish mother, it lectures and berates you for everything you try to put into or take out of the bag.
A creature within the bag that can hear (though it need not understand language), must succeed on a DC 12 Wisdom saving throw at the end of each minute it spends inside the bag or take 1d6 psychic damage and have disadvantage on the next attack roll it makes before the end of its next turn.