Koopa Troopa

Koopa Troopas ノコノコ in Japan are turtle-like creatures. These are the oldest organic regular enemies in the series, debuting in Mario Bros. for the arcade (previously, all non-boss enemies were merely barrels). They come in multiple colors, including green, red, blue, and yellow. In more recent Mario games such as the New Super Mario Bros. series, green Koopa Troopas will walk in a straight line from wherever they are placed on the map, whereas Red Koopa Troopas will pace a certain area of land. They first walked on four legs, but in later games they have both hands and feet. Koopa Troopas, unlike real turtles, can not only be separated from their shells, but re-enter any empty shell if they choose to. The shell-less Koopas, called Beach Koopas, are depicted wearing either an undershirt, boxers, or both under their shells, and can walk upright even without the shell. The empty shells may be used as projectiles, which have become a fixture in all Mario Kart games. Most Koopas are members of the Koopa Troop (Bowser's army), but both Super Mario 64 and the Paper Mario series include friendly Koopas, such as Koopa the Quick (Super Mario 64) and Kooper (Paper Mario). Flying versions with wings, first introduced in Super Mario Bros., are called Koopa Paratroopas. Both Koopa Troopas and Koopa Paratroopas make cameo appearances in Super Smash Bros. Melee and Super Smash Bros. Brawl as enemies. Giant Koopa Troopas called Gargantua Koopa Troopas were introduced in Super Mario Bros. 3 and reappeared in Super Mario Galaxy 2 only in Supermassive Galaxy.

The Koopa Troopa, based on the kappa, a mythical creature, was preceded by the Shellcreeper in Mario Bros. as an enemy that could only be defeated by hitting the floor underneath it (to stun it) and then going up onto its platform to deal the final blow. Series creator Shigeru Miyamoto had a fellow designer draw the Koopa Troopa. He drew a realistic design that didn't fit well in the Mario series, so Miyamoto made his own design. While the design had quite a large head, Miyamoto validated it by suggesting that it looked like a tortoise. He and Hirokazu Tanaka, a frequent sound designer for Nintendo at the time, discussed what the insides of a turtle looked like. Miyamoto wanted to make it easy to tell when a turtle was going to jump up, but he felt that the twitching of the shell was not enough warning to tell players when it would flip over. Tanaka suggested that the turtle be launched from its shell when flipped over, and eventually attempt to reenter it. While this was not true to the actual anatomy of a turtle, whose shell develops from its spine, Miyamoto felt that it was the best way to convey when they were a threat again. Super Mario Bros. originally featured the Koopa Troopa as its only enemy. However, they chose to add more enemies after people said that the Koopa Troopas were way too tricky to defeat due to it being a two-step process.

The design of the Koopa Paratroopa came from Mario developer Takashi Tezuka in an attempt to add a flying character to Super Mario Bros., but did not have enough space to include such a character. Tezuka suggested that they put wings on the Koopa Troopa and call it "Koopa Paratroopa", which Miyamoto did not think would work. However, once it was finished, Miyamoto felt that it looked cute. An item called the "P Wing" was added to Super Mario Bros. 3, which was based on the Koopa Paratroopa.

A variety of Mario-related merchandise depicting Koopa Troopas have been produced over the years by Nintendo; this merchandise includes plush dolls, mini figures, bottlecaps and plush keychains. The various merchandise given out on King Koopa's Kool Kartoons was often adorned with the name Koopa Troopa as well. Their signature shell was included as a player piece in the Nintendo Monopoly game. A Koopa Troopa was featured in a line of six-inch-tall plush toys based on characters from the Mario series.

A satirical article was written by The Pitt News columnist Ben Korman, criticizing the Mario series for its offensive treatment of the Koopa Troopas, stating that the character Mario was rewarded for his slaughter of "innocent, healthy turtles". GameDaily listed Koopa Troopa as the eighth best Mario enemy, calling them the most common enemies in the series next to the Goomba.