Koopa is a turtle-like creature who first appears in original Super Mario Bros. for NES. They first appeared in two colors: red and green. Also, they appeared in two variations: Koopa Troopas (normal) and Koopa Paratroopas (パタパタ (Koopas with wings on their shells). It one of the few enemies of Mario universe who cannot be killed just by jumping on them. If jumped on him once, it comes inside a shell. The second time the player jumps on the Koopa, the Koopa shell starts moving forward until it hits a wall and bounces back. It can be stopped after jumping on it again. If left shell alone, Koopa will come out of its shell again. If player jumps on Paratroopa, he transforms into normal Koopa Troopa. In Super Mario World was introduced two new color variations: yellow and blue.
In A Super Mario World
Numerous Koopa Troopas, alongside their winged brethren, Koopa Paratroopas, appear in the first episode during Mario's killing spree with the Master Sword. Despite coming in huge numbers, they prove to be not match for Mario and the Master Sword and ended up defeated and massacred by him.
In Super Smash Flash, the Koopas appear in the first stage of the Adventure mode called Super Mario World along Flying Goombas but unlike the Mario games, its shell cannot be used as a weapon as one hit destroys the whole Koopa. All the Koopas in this level are red-shelled, despite that, they behave like their green-shelled counterparts who keep walking and do not turn around when they encounter an edge, instead they fall.
In Super Smash Flash 2
As a background character
Two Green Koopa Troopas in their original 8-bit form can be seen walking back and forth in the background from Mushroom Kingdom, an odd behaviour for this kind of Koopas, as the Green variants are not supposed to turn around after coming on an edge, this behaviour is exclusive to Red Koopa Troopas.
As an enemy
This section contains information of a formerly confirmed feature.
The original source that confirmed the subject has otherwise become obsolete, outdated or deprecated and has yet to be re-confirmed by an official modern source.