Main story:
The story is set in a dystopian society, where a man recalls the time he found a strange crab-like creature that seemed lost. He asks people throughout the city about the creature's whereabouts, but no one seems to know or care. Then, he goes to a facility advertised on TV for lost and found items, where he's informed by a janitor(?) working at the place to bring the creature to a different location if he really cares for it. After some traveling, the two reach the location and to the man's surprise, there were tons of creatures similar to the crab in the sense that they all looked quite goofy. He bids farewell to the creature and hasn't thought back to it much since.
The lost thing:
I believe the lost thing symbolizes childhood innocence/joy/imagination that tends to get fade away as you grow up and get into the "real world". There's a stark contrast between the location filled with the lost things and the human society, with the former being blindingly colorful and the latter being monotonous. No one in the city seems to care because they've either lost interest in it or are too busy with their own problems to give it any attention.
