The Bottomless Bag is a small purple drawstring bag with peach strings, and a candy pattern.
Role in the film
When Joy and Sadness were venturing around Long Term Memory, Joy notices a creature taking memories, and placing them in his bag. After a brief chase, Joy figures out the person is actually Bing Bong, Riley's imaginary friend. Seeing how hard it is for Joy to hold onto five core memories, Bing Bong offer to empty out his Bottomless Bag to let Joy put them in. Bing Bong empties out the bag, which is filled with hundreds of memories, and even some junk that gets stuck at the bottom, like a boot, an anchor, a trumpet, a kitchen sink, and Bing Bong's Cat.
Later on in the film, Riley falls asleep, and the Train of Thought stops moving. In an attempt to wake Riley and get the train moving again, Joy, Sadness and Bing Bong break into Dream Productions to create a dream that will make Riley wake up. Before Joy and Sadness jump into action, Joy hands the bag over to Bing Bong to make sure he doesn't lose it. Due to Joy and Sadness' interference in the dream, one of the Mind Workers calls security, and they arrest Bing Bong. To Joy's disappointment, Bing Bong is still holding onto the bag. After rescuing Bing Bong from the Subconscious, Joy gets a hold of the bag again.
After Joy and Bing Bong fall into the Memory Dump, the two quickly notice Bing Bong's discarded wagon, and they attempt to use it to escape. After failing two times, Bing Bong suggest that they try one last time out of confidence. The moment they start flying, Bing Bong jumps off, making the wagon lighter, and allowing Joy to escape. Bing Bong fades away from existence leaving Joy the owner of the Bottomless Bag.
In an attempt to catch a cloud-sitting Sadness and get back to Headquarters in one shot, Joy heads into Imagination Land, and goes to the Imaginary Boyfriend Generator to produce dozens of boyfriends, which all fall into the bag. Upon having enough boyfriends, Joy takes the bag, runs torwards the edge of a cliff, and flips the bag upside down, making all the boyfriends spill out and stack up into a large tower.
The Bottomless Bag is last seen when Joy pulls out all of the core memories to let Sadness turn them blue to let Riley express her true feelings about missing Minnesota. It is unknown what Joy does with the bag after this moment, though she could have stored it away sometime later.
- The joke of Bing Bong pulling out a kitchen sink from his Bottomless Bag could be a reference to the idiom, "Everything but the kitchen sink," which means to find many items, most of which are unnecessary to use, like all the memories and junk Bing Bong had in the bag.