It’s a commentary on slavery, featuring a character that digs from the top of a pile of something, coal, perhaps, down to the bottom all through the short.
The movie is currently not available onine
The Wild Robot
Despicable Me 4
Inside Out 2
Kung Fu Panda 4
The Bad Guys: Haunted Heist
Ultraman: Rising
No Time to Spy: A Loud House Movie
Transformers One
Saving Bikini Bottom: The Sandy Cheeks Movie
The Inseparables