Big Koopa Troopa

Big Koopa Troopas, or Big Koopas, originally known as Giant Koopas, are gigantic versions of normal Koopa Troopas that are seen around the Mushroom Kingdom.

Super Mario Bros. 3
Giant Koopas appear in Super Mario Bros. 3 and reside only on Giant Land (along with other gigantic creatures like Grand Goombas and Piranhacus Giganticus). Mario and Luigi have a harder time avoiding these Koopas because of their increased size. Despite this, if the plumbers stomp on a Giant Koopa, it hides inside its green or red shell, just like an average-sized Koopa Troopa does when it feels threatened. Once inside, the plumbers can kick their shells away. In the Nintendo Power Strategy Guide, they are split between Green Gargantua Koopa Troopas and Red Giant Koopa Troopas.

Super Mario 64
In Super Mario 64, a single Giant Koopa known as Koopa the Quick appears in the game as a friendly racing rival to Mario. He hails from Tiny-Huge Island (an island filled with both miniature and gigantic enemies) but he is the only Giant Koopa seen in the game.

Super Mario Galaxy 2
Giant Koopas reappear in Super Mario Galaxy 2 in the Supermassive Galaxy. Only three are found patrolling a solitary planetoid where they attempt to flatten Mario if he gets in their way. They can only be defeated with a Spin Drill by drilling into their belly from the opposite side of the planet. If Mario performs a Long Jump on a Giant Koopa so that he catches up with it each time, he can get 1-UPs for every consecutive time he stomps onto it after seven initial consecutive jumps, allowing maximum lives to be gained.

New Super Mario Bros. U / New Super Luigi U
Big Koopa Troopas appear in New Super Mario Bros. U, and are common enemies in Jungle of the Giants. The player is no longer able to carry their shells in this game. Additionally, their shells are able to break through normal-sized Brick Blocks without bouncing off. Unlike previous games, the Big Koopa Troopa is bipedal and wearing shoes.

Big Koopa Troopas also appear in New Super Luigi U, in Giant Swing-Along.

Super Mario Maker / Super Mario Maker for Nintendo 3DS
Big Koopa Troopas come in green and red varieties in the level builder game, Super Mario Maker and Super Mario Maker for Nintendo 3DS. In the Course Maker, after the player drags a Super Mushroom onto a standard Koopa Troopa, the enemy grows in size. Just as in New Super Mario Bros. U, its shell cannot be carried, and this applies even when playing in Super Mario Bros. 3 style, whereas in the said game, the player could transport the shells of Big Koopa Troopas. Big Koopa Troopas now have the ability to break Hard Blocks.

Super Mario World 2: Yoshi's Island
In Super Mario World 2: Yoshi's Island, a regular Koopa Troopa named Hookbill was transformed by Kamek into a giant-sized Koopa in order to stop Yoshi from reaching World 5. It acted as the boss of World 4.

Paper Mario
In Paper Mario, a greedy and nearsighted Giant Koopa named Kent C. Koopa appears as an optional boss in the game. Notably, he has taught the Koopa Bros. how to fight, and is known as a 'bully,' who refuses to let Mario pass unless Mario pays 100 coins. If Mario disobeys him, Mario and his partners must fight Kent C. Koopa to get him to return to Koopa Village.

Mario & Luigi: Superstar Saga / Mario & Luigi: Superstar Saga + Bowser's Minions
Giant Koopas appear as obstacles in Mario & Luigi: Superstar Saga. In this game, they are cross-eyed and have oblong shells which extend up from their backs, behind their heads. They block certain paths in the Beanbean Kingdom and recite the line, "Derr... No matter what you hit me with, you can't knock me down. ...I think." They cannot be stomped; however, Mario's Firebrand Bros. Dash technique can knock them down, forcing them to move aside. A non-obstructive one also appears in a house in Beanbean Castle Town. In Mario & Luigi: Superstar Saga + Bowser's Minions, they have been redesigned to be larger and resemble ordinary Koopa Troopas.

Super Mario Bros.: Peach-hime Kyushutsu Dai Sakusen!
In the 1986 anime Super Mario Bros.: Peach-hime Kyushutsu Dai Sakusen!, an unusually large Koopa Troopa appears during a walking montage scene. It looks curiously at a passing Mario, Luigi, and Kibidango before jumping on them. However, Mario uses the power of the Super Mushroom he had recently acquired to push it off of them by growing even larger than it.