You’d be forgiven for thinking that Finding Nemo didn’t really need a sequel. It was a completely charming, yet contained adventure, wrapped up pretty neatly. But, it was a very, very successful Pixar movie and, these days, that means sequel.
The skit, shot like a '90s sitcom, shows a black family with butts so absurdly large that they get in the way of everyday functions like walking around without knocking things over. That's it. That's the whole joke.