I just thought of the most evil shit you could do with this.

They buy the bag and it comes preloaded with a couple lil crocheted trinkets that are cutesy and like grandma made it for adventurers. A lil mealkit, a ration pack, a lil sword and shield but also a doll. As they slowly start to realize what the bag does they remember the doll and start freaking out about what if it was a person who went in there to hide and got turned and we gotta fix 'em! Ends up being a whole quest line to unfuck the bag, the bag items and specifically this doll. At the very end they undo the doll and it turns into a wooden doll. Then when laughter/disappointment just getting to the right point, have the doll talk. Get the joke of it being a doll and they get the expectation they wanted of it being a living being they saved.

Or, a bag of holding embedded in a doll’s butt. Try being taken seriously when you’re fisting a plushie for a magic potion.

bag of holding, but the encantment is on the futz so it's only like 10% larger on the inside.