This stage is Motley Bossblob’s Big Battle (6-C). This complete walkthrough will provide you with a 100% video playthrough. Remember to grab the double cherry before you head into the boss fight. In addition, make sure both of your copies ride on the platform.
Game Play Walkthrough Video
The key to beat the boss is to be patient and dodge the boss’ jumps. On his final jump, his blobs would fall into smaller pieces, break a couple of pieces and deal the blow to Motley. After 3 hits you will claim victory and a green star for your effort.