Mechakoopa

Mecha-Koopas are one of Bowser's many minions. They are small mechanical versions of Bowser himself. They are a mixture between a Koopa and a wind-up toy. They have a wind-up key on their back and their appearances feature several mechanical appendages. They walk in a rhythmical way and they must wind themselves up again from time to time in order to keep moving.

Super Mario RPG: Legend of the Seven Stars
In this game, Bowser will use a giant, green Mecha-Koopa as a weapon in his attack, Bowser Crush.

Super Mario World
Mecha-Koopas make a short appearance in Super Mario World, where they are only seen in the last level. In this game, they get paralyzed for a short time when stepped on, so Mario can kick them around, pick them up and throw them. When they get thrown, however, they won't get very far like regular Koopa shells do. They are also not effected by ordinary kicks, as they just freeze, giving the player a chance to throw them somewhere; however, they are vulnerable against the Spin Jump, which turns them into dust.

Mecha-Koopas are also prevalent in Super Mario World 's final battle, in which Bowser throws them off of his Koopa Clown Car. Mario/Luigi must throw them so they hit Bowser's head in order to defeat him.

Mario & Luigi: Superstar Saga
Smaller versions of Mecha-Koopas make a short appearance in Mario & Luigi: Superstar Saga as conductors to complete circuits of electricity in Bowser's Castle. (Unnamed toy mice held the same purpose previously in Woohoo Hooniversity.)

Super Mario Galaxy
Mecha-Koopas also appear in Super Mario Galaxy with a new look. They are found in Toy Time Galaxy and can breathe flames for fairly long amounts of time. They can only be defeated with a Ground Pound and stunned with a Star Spin.

Yoshi series
Mecha-Koopas appeared in Bowser's Castle in Yoshi's Safari. In this game, they could be stunned with the Super Scope's bullets, but would awaken momentarily unless Yoshi walked into them.

Mario Party 5
In Mario Party 5, the player will fight a group of Mecha-Koopas in the first part of the final battle. They would walk around, occasionally flashing red, then unleashing fiery breath. Jumping on them once will cause them to explode. The player must throw them at each other, or just avoid them all for 60 seconds. Jumping on a Mecha-Koopa while it's breathing fire will hurt the Player.

Mario Party 7
In Mario Party 7, Mecha-Koopas appear in the one-player, Bowser mini-game, Tunnel of Lava!. Here, one Mecha-Koopa will eat the key to freedom from Bowser's mini-game area and will retreat into a hole, only to come back a second later with many other Mecha-Koopas. The Mecha-Koopas would then circle the character, who would have to stomp on the correct Mecha-Koopa's head while they circled him/her before Bowser stomped on the character 30 seconds later. The Mecha Koopas had an attack pattern similar to that found in Mario Party 5, except all the Mecha-Koopas will breathe fire simultaneously.

Mario Party Advance
In Mario Party Advance, a Mecha-Koopa owned a library, and appeared to be an arithmetic genius. The player must complete a quest for the Mecha-Koopa in order to get a Gaddget. The quest consisted of answering three simple math problems; after answering the three questions correctly, the player will be awarded with a Gaddget.

Mario Tennis series
In Mario Power Tennis, Mecha-Koopas make a small appearance in the background of the Bowser's Castle court.

Super Mario World TV series
Mecha-Koopas, renamed Mechkoopas, and occasionally called by the generic name Robot, appeared in several episodes throughout the Super Mario World animated series.

Their first appearance was in the episode "Send in the Clown", where a Mechkoopa riding a bicycle acted as the tight-rope walker in Bowser's circus, the "Koopaling Bros. Circus". After the "Koopaling Bros. Circus" was revealed to be an elaborate trap, this Mechkoopa, along with several Chargin' Chucks, began to chase Mario through Neon Castle. This Mechkoopa was eventually defeated by Mario, who had gained the cape ability.

Later in "Send in the Clown", Bowser attempted to defeat Mario by throwing several Mechkoopas at him from the Koopa Clown Car. Mario, after knocking a Mechkoopa unconscious, managed to defeat Bowser by hurling the Mechkoopa at his Koopa Clown Car, causing it to malfunction and crash in a very similar way as Super Mario World.

Mechkoopas next made a small appearance in the "The Night Before Cave Christmas", where several of them attempted to attack Mario and Yoshi, who had broken into Neon Castle. Mario and Yoshi managed to escape these Mechkoopas by using a Feather to transform into Cape Mario and fly-away.

The last appearance of Mechkoopas in the Super Mario World TV series was in the show's final episode, "Mama Luigi". Here, Bowser sent a brigade of Mechkoopas after Mario and Luigi as the two explored Bowser's throne room looking for Yoshi. These Mechkoopas, after chasing Mario and Luigi, were defeated when Yoshi simply devoured them.

Super Mario Adventures
In the Super Mario Adventures comic, the Koopalings, after having captured Mario by chance, used two Mecha-Koopas to send a message to Luigi, Toad and Yoshi. Either they exchange Princess Toadstool for Mario, or Mario will be killed, after saying this, the Mecha-Koopas symbolically burnt a Mario Doll with the flamethrowers in their mouths. Luigi then said, "That's Blackmail!". Luigi, with help from Friendly Floyd, managed to trick the two Mecha-Koopas by making them take him to the Koopalings instead of Princess Toadstool.