Super Paper Mario Glitches (Wii)

In light of a recent kidnapping of Princess Peach, Mario and Luigi head to King Bowser's castle to retrieve her, only to find that Bowser wasn't responsible for it. It is then revealed that the true kidnapper is Count Bleck, a dastardly sorcerer who wields an ancient, prophetical tome called the Dark Prognosticus.

In addition to Princess Peach, he kidnaps Luigi and Bowser, along with all of Bowser's army. The evil Count then employs the hypnotic powers of his right-hand woman, Nastasia, and forces the marriage of Princess Peach to Bowser in order to, as the Dark Prognosticus foretells, unleash a destructive power known as the Chaos Heart. Count Bleck uses the Chaos Heart to open an interdimensional rift known as "The Void", which will eventually grow large enough to engulf the entire universe.

Mario meets a Pixl, a type of fairy, named Tippi, who has come in search of Mario for he matches the Hero, described in another occult book called the Light Prognosticus, who is able to halt the impeding doom of The Void. In order to banish the Chaos Heart and reverse the destruction, the Hero requires the eight Pure Hearts, artifacts created from genuine love. Mario then sets out on his quest with Tippi at his side, as well as the other three Heroes (Peach, Luigi, and, in a fit of ironic oddity, Bowser), to gather the Pure Hearts and stop Count Bleck and his minions from obliterating all existence.
(Wikipedia)

Glitches

Destroy a chunk of World 1-2 temporarily
As Mario, go to the shop at the end of World 1-2. When you enter the building, flip to 3-D mode and go to the wall on your left. Run into the wall and switch to 2-D mode. To your left will be a sign. Walk into it and you should be sticking out halfway. Flip to 3-D mode. Jump to the to enter another building. It will not look like anything. Exit. It will look like you came out of the shop, but you will come out of the building next door. If you return to the shop, you can talk to the door. Go inside, and the shopkeeper might be facing the wrong way. If you jump left and forward, you will enter an invisible black world. If you jump in a pipe, Mario will scrunch up. You can still complete the level, but the star blocks are invisible.

Quick Boomer switch
Take Boomer out. Put him down then quickly go to the Quick menu and switch Pixls. Boomer will still be there. When he blows up he will instantly disappear and the Pixl you asked for will instantly appear.


Here's some gameplay footage below: