Koopa Troopa

Koopa Troopas (commonly shortened to Koopas or occasionally Troopas) are turtle-like creatures with removable shells that come in many different colors, with red and green Koopa Troopas being the most common; green Koopa Troopas usually walk back and forth without any concerns for pits or other obstacles, and red Koopa Troopas usually walk back and forth without falling off of their platforms. They are common enemies in the Mario franchise, usually displayed as foot soldiers of the Koopa Troop, under the direct leadership of Bowser. Since Super Mario 64, however, not all Koopa Troopas work for Bowser (or any other villain), some of whom even act as allies to Mario during his adventures, and have appeared as playable characters in various spin-off games starting with Super Mario Kart. They are notable for the many uses of their shells in the Mario franchise.

Koopa Troopas, along with Goombas, are Mario's most common foes.

In games
Koopas are usually enemies in these games.

Battle of the Multiverse
Koopas are enemies in this game.

Brutal Mario
In Brutal Mario, Koopa Troopas walk on two legs and wear shoes. An ejected Koopa will slide out of its shell, wearing only a t-shirt, and will crawl back to its shell after being temporarily stunned. Their shells can still be carried. A Koopa that reentered a yellow shell would flash and turn invincible and chase after Mario, sliding around inside the shell.

Super Smash Flash 1
In Super Smash Flash, the Koopas appear in the first stage of the Adventure mode called Super Mario World along Flying Goombasbut 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.

Mushroom Kingdom Fusion
Koopas are behaving like they always have. Stepping on one will retreat it into it’s shell and you can ether kick it or grab it.

Happy Tree Friends Adventures Series
Koopas are basic enemies in the HTFA series.

In Movies
Koopas would be mooks working for Bowser.

Super Smash Adventures
Koopa's are mooks working for Bowser.

Mario and Kirby's Superstar Legacy
Koopas are seen in this movie along with some variants. Their will also be a Koopa character making an appearance.

In Tv Series
In the tv series, Koopas make cameos