Giga Cat Mario

Giga Cat Mario is a form of Mario that only appears in Super Mario 3D World + Bowser's Fury, albeit exclusively in the Bowser's Fury mode. It is a larger, more powerful form of Cat Mario and is only accessible after collecting a certain amount of Cat Shines to awaken a Giga Bell, of which there are only three in Lake Lapcat. Mario assumes this form in order to fight Fury Bowser.

Giga Cat Mario's fur takes on a more radiant golden tint than regular Cat Mario's, with a lion mane and a tuft at the end of his tail, resembling those of a . While Mario transforms into this state, he strikes the same pose that regular Cat Mario does in official artwork.

Unlike other giant transformations such as Mega Mario, and in a similar vein to Big Mario, Mario is not invulnerable in this form, still being able to take damage, causing him to return to his Super form, or his Small form if he is damaged a second time (though he stays giant). The Giga Bells respawn after Mario has collected one, allowing Mario to return to his Giga Cat form if he takes damage by collecting one again.

At the end of the final battle against Bowser, Plessie obtains all three Giga Bells simultaneously and transforms into , which differs from Cat Plessie only in its overall size being much larger and in its eyes never staying wide open. After the ending cutscene, the camera zooms out to reveal that said cutscene took place on Giga Cat Plessie's back. For the rest of the game, Plessie changes to Cat Plessie.

After collecting all 100 Cat Shines and then defeating the final boss of the Bowser's Fury mode again, Cat Mario's appearance in the mode is changed to resemble Giga Cat Mario's, albeit much smaller (though the Lucky Bell collar is retained); this change is only aesthetic and does not affect Mario's moveset in any way.

Giga Cat Mario also appears in Super Smash Bros. Ultimate as a primary, Advanced-class, Shield-type spirit, introduced during the five-day "Bowser's Fury" spirit event that began on April 9, 2021. When equipped, the fighter's jump height is increased. He is represented by a giant Mii Brawler wearing the Cat Hat and Suit and teamed up with Bowser Jr. in his spirit battle, which takes place on the Ω form of Find Mii. "The Great Tower Showdown 2" from Super Mario 3D World serves as the battle's music.