Mission: Bugaboom's back
Difficulty: 3/10
Attacks: Chomp, Bomb, Ram.
How to defeat: Get a cloud flower for this one folks. Dodge Buga's chomp attack and jump on his back. Ground pound him to lose 1/3 of his health. After this he will begin to fly around. Make a cloud and wait for him to come. When he does, jump on him and pound him. After another cutscene, he will become enraged. He will now fly faster and produce more bombs. When he gets close, he may rotate so you can't hit him. But you can actually hit him anyways. Land that bugger and earn your star!
Mission: Rock and Rolliodilo
Difficulty: 4/10
Attacks: Roll, Ram.
How to defeat: Get a rock mushroom. First, dodge his ramming attack, then roll into his back. Now he will start to use his roll attack. Dodge to the sides until he trips up. Then strike. Now he'll jump after every attack so you'll need to dodge quickly to not get hit. When he trips up again, finish him and obtain your star!