Bag of Holding

It is just a  normal day in your normally quiet village of Arcton. You, Mohini, are sitting beneath the town's mythical Baobob tree. The tree drops a bag for you. Upon further instructions, the bag indicates, it can hold one and ONLY ONE item in it, but that item can be of any size.  Would you like to assist your grandmother with her groceries? Maybe the town's fountain needs to be moved? Perhaps …