Super Dimentio has a very unique and disturbing appearance as he has the head of Luigi but the body of Dimentio. He also has long arms and long legs and a long neck.
Dimentio, after finally have put all of his plans together, fuses with Luigi and the Chaos Heart to form this monstrous beast. After sealing Tippi, Count Bleck, and Nastasia in Dimension D, Super Dimentio turns invincible and plans to take down remaining the heroes of the Light Prognosticus. Super Dimentio nearly succeeds until Tippi suddenly comes back from Dimension D with the Pure Hearts which makes Super Dimentio weaker. After a long fight, Super Dimentio is defeated. However, Super Dimentio (though now really Dimentio) says he will leave behind a shadow of himself to keep controlling the Chaos Heart. He issues one final "Ciao" before spitting out Luigi and is fully destroyed. The still active Chaos Heart was eventually stopped thanks to a sacrifice by Count Bleck and Tippi and the worlds weren't destroyed foiling Dimentio's plans.
In battle, Super Dimentio has many attacks. Super Dimentio mainly attacks by slamming his fist at Mario, Peach, or Bowser. He can also do a Ground Pound-like attack that can cause up to 10 damage if it connects. Super Dimentio can also fire lasers rapidily causing Mario and the others to dodge. If you use shielding attacks for too long (ex. Peach's Parasol), he uses a pal-pill-like attack with a ton of mini-Luigis that die in one hit, even if they hit the wall.
Anyone and everyone can be useful in this final fight. Mario can use his speed and athleticism to jump up blocks and hit Super Dimentio with a jump (or a Ground Pound using Thudley). Peach's umbrella can block the lasers and Bowser's sheer power can make the fight end quicker given he is using Carrie. After many attacks, Super Dimentio is defeated.
- Like all of the final bosses of the Paper Mario series, Super Dimentio starts off invincible until something gets rid of his invincibility.