Super Paper Mario/Chapter 8: Castle Bleck

Chapter 8-1: The Impending Darkness
Boss: O'Chunks-Bowser is the only character who plays agaisnt this boss. He will vanish afterward, and won't appear until your fight with Count Bleck at the end of the chapter. This will happen to other characters though the rest of the chapter.

Chapter 8-2: The Crash
Boss:Mimi-Peach is the only character you can use agaisnt this boss. Afterward, Peach vanishes and appears again at the start of the battle with Count Bleck.

Chapter 8-3: Countdown to Destruction
Boss:Dimentio-Luigi is the only character you can use to fight Dimento, and leaves the group after the battle and returns at the start of the fight with Count Bleck.

Chapter 8-4: Tippi and Count Bleck
Head through the door at the end of the first hallway. Inside, you'll hit a dead end. Use Tippi's pointing powers to discover a door you can continue through.

Cross this room via the moving platforms with carefully timed jumps. However, along the way, you'll come across a wall twice that blocks further progress - flip to 3D here to and leap to the bordering platforms to get around. Also, you'll occasionally have to wait a few moments for a platform to lower enough for Mario to reach it, so be patient. Enter the door on the far side. Jump across the first four sets of platforms and land on the stationary platform. Flip to 3D to find a pipe on the left.

After taking the pipe, flip to 3D, then use Dottie to shrink in size and enter a small tunnel (visible through the break in the white lines) along the wall. Flip to 2D to traverse through the tunnel to a chest containing the Castle Bleck Key. Exit back through the pipe and cross the remainder of the room to unlock the door.

Boss1:Count Bleck HP:150  Attack:8

Boss2:Super Dimentio HP:200  Attack:6

Note: After Tippi leaves the group at the end of the game, you can buy Tipton (an almost exact copy of Tippi) for 999 coins from Francis, the boss of chapter 3.