Walkthrough: As you reach the top of Sky Garden Tower, you will again be approached by the Broodal Group. This time, you'll be challenged by the final of the four Broodals. Unlike the other Broodals, this guy will stay in the middle of the arena and not chase you, choosing to cover the dirt with more poisonous goop. Use Cappy like before to clear away the goop and create a path to the Broodal, using Cappy to make him lose his hat while you're at it. After losing his hat, he'll try tossing more goop at Mario. Avoid it, and then jump on his head like you did the other three Broodals.
Per usual, the Broodal will jump in his hat. It will spin around, spewing forth more poison to wherever it bounces. Use Cappy to deflect the substance, sending it back to where it came until he finishes his rampage. The next phase will begin afterward, with the Broodal spew all the more goop this time around and at larger distances too. Like before, stay on the move to dodge it, clear a path to the Broodal by using Cappy. Knock of his hat again, and do the same as before.
In the final phase of the battle, the Broodal will cover almost the entire area with goop to begin, forcing Mario to head for the edge of the arena to dodge it. Once he's done, do exactly as before and clear a path to him using Cappy. Watch out for the shots of vomit he'll spit your way, removing his cap like before so and nailing one final jump to his head. This will defeat the Broodal and thus end the match, earning yourself another Multi Moon.