S1·E6 King Scoopa Koopa

King Koopa goes into the fast food business and his food is a hit with everyone in Dome City, except for the Princess. But no one knows that Koopa sneaked in a side effect for those who eat his Egg Scoopa Koopa sandwiches, turning them into Chickadactyls. Only Mario and the Princess remain unchanged so it's up to them to stop Koopa.