In this cartoon, Mickey Mouse and Pluto are traveling down an African river with a bunch of cargo. They are then captured by cannibals. Most people have not gotten the chance to see this cartoon because it has never been released on video,laserdisc, or DVD and is not (but may have been at one time) shown on the Disney Channel or Toon Disney. The reason for this is because of its strong use of cannibalistic caricatures that Disney might consider offensive to people. After one of the cannibals dips a saxophone into the pot he's cooking Mickey in, he sips the soup out of it. Mickey grabs it and soon they're all jamming to "The Darktown Strutter's Ball." I did notice that the king cannibal's laugh was quite similar to Goofy's and he may have been voiced by Pinto Colvig as well.
EDIT: This cartoon is now available on the Walt Disney Treasures set Mickey Mouse in Black and White Volume 2.