Bowser's Villa 8-6
From the Super Mario Wiki
Like in Shriek Mansion 3-6, the level starts off with the player floating down, whilst avoiding various kinds of Boos. After this is the mini-boss fight with Army Hammer Bro, who, despite throwing bigger hammers and calling for reinforcements via the Rage vibe, is defeated after being hit five times with Perry.
After this is the final boss fight with Bowser. At the start of the fight, Bowser throws hammers, charges into Princess Peach, and breathes fireballs and a massive fiery blast. To deal damage to Bowser, the player needs to use the Rage vibe on his face. After the second hit, Bowser will use the Joy vibe to start ground pounding, which will create shockwaves that damage the player. After the third hit, Bowser will start throwing giant hammers while using the Gloom vibe. On the fourth hit, he uses Rage to speed up his attacks.
After the fifth hit, the second phase of the boss fight begins. Bowser becomes giant (in this form, he is referred to by the game's enemy glossary as "Bowser 2"), and attacks by pounding his hands, which will cause either Spiked Balls or Bob-ombs to rain down. Bowser can also attack by sending out a ring of hammers, or breathing fireballs or continuous flames. To damage Bowser, the player needs to throw Bob-ombs at his face, but only when they are about to explode. After the fourth hit, Bowser will bring up a barrier around his face, and try to completely heal himself with the Calm vibe; this can be stopped by using Joy or Rage. On the fifth hit, Bowser will be defeated.
Redoing this level after clearing it makes Bowser's second phase tougher, as he needs two Bob-omb explosions to lose one hit point.