A cartoon movie from a while ago, maybe 10-15 years. I don’t remember much  except people were living in a plastic globe, in like an alternate universes maybe because there was sand all around the plastic circular wall. They ate food that was being produced with in this plastic sphere globe. Every month they would choose people to dance in a circle and one would be sacrificed to the monsters And the person would be pulled under them in trade for their protection. All I remember is that someone was chosen to be the monsters food and then the rest the movie is  The main actor, a man, who tried to save her.