Mario Bros. (Arcade/NES/GBA)Edit
The original "Shellcrawler" appearance from the Mario Bros. game. They wer replaced by Spinies in the GBA version.
Super Mario Bros. (NES/SNES)Edit
Koopas are turtles that can be stomped on but it retreats in it's shell instead of disappearing.While they are in this state, they can be jumped on and used as a projectile to attack other enemies, or hit bricks and ? blocks. Mario can also get hit by the shell, and he will either revert to his small form or lose a life if he gets it by the moving shell. Green Koopa Troopas walk off of blocks, while Red Koopa Troopas turn around corners instead.
Super Mario Bros. 3 (NES/SNES)Edit
They reappear here with similar behaviour to Super Mario Bros. for NES. They can be picked up and be thrown when they are stomped on.
The game also features the first appearence of Big Koopa Troopas.
Super Mario World (SNES) Edit
Koopa Troopas gain a significant overhaul in Super Mario World, It marks the first time Koopa Troopas are seen walking on two legs in-game and wearing shoes (which later became the standard look for them). When a Koopa Troopa is stomped on, it is knocked out of it's shell, becoming a Beach Koopa. The knocked out Beach Koopa will be stunned and vulnerable for a short amount of time. A Beach Koopa has to walk back to it's shell in order to reclaim it.
This is the first game to introduce Koopas wearing Yellow Shells and Blue Shells. Also, if Yoshi eats certain color shells, then he will gain abilities: Green shells do nothing, red shells allow Yoshi to spit fire, yellow shells allow Yoshi to cause a small earthquake every time the player lands after a jump, which defeats any enemies who are on the ground nearby, and blue shells allow Yoshi to fly for a short period of time.
The color of the shells also determine the behavior of the Koopas, Blue-shelled Koopa Troopas act like Red-shelled Koopa Troopas, but they move faster. A Blue Beach Koopa won't get stunned when it's kicked out of it's shell, and it will kick any shells in it's path. If the player attempts to launch a shell back at Blue Beach Koopa, it will grab it and throw it back to the player. Yellow-shelled Koopa Troopas are unique and tend to chase after Mario, but act like faster green-shelled Koopa Troopas in movement. When yellow-shelled Koopa Troopas lose their shell, a coin pops out. Also, when a shell-less yellow-shelled Koopa finds a new shell, it will turn into a Kamikaze Koopa and chase Mario. It will be invincible to most of Mario's moves, however, Yoshi can eat this shell and gain all three shell abilities for a limited time, and a spin jump will also destroy this shell.
- In Super Mario World, after the player completes the Special World, or find all exits in Super Mario World: Super Mario Advance 2, all Koopa Troopas (except climbers) become Mask Koopas, with their respective shells becoming round masks that vaguely resemble Mario.