A robo-suit is a robotic full-body suit that can be worn to grant the wearer(s) with numerous abilities. There have been two robo-suits that made appearances, both of which appear during The Super Mario Bros. Super Show! episode "Robo Koopa". Both robo-suits are designed by Dr. Nerdnick, although they vary greatly in design and function.
Robo Koopa's suit
The first robo-suit built by Dr. Nerdnick is worn by King Koopa. King Koopa somehow convinces Dr. Nerdnick into building it for him, and wears it to wreak havoc on Robo Land, thus attracting the attention of Mario and friends. While wearing the suit, King Koopa goes by the alias of Robo Koopa. As Robo Koopa, King Koopa is a seemingly unstoppable force, and comes close to defeating Mario. However, Dr. Nerdnick and his assistant Bunsen trick Robo Koopa into triggering the robo-suit's ejector seat, thus sending King Koopa flying out of the suit. Dr. Nerdnick later converts this robo-suit into a "robo pizza oven."
Powers and abilities
The second robo-suit, unlike the first, is given an actual name: the Plumbinator. Additionally, it required two operators in order to function. Dr. Nerdnick builds it entirely out of spare parts found in a junkyard, thus limiting the suit's full potential as a counter to the more refined Robo Koopa. Wearing the suit, Mario and Luigi challenge Robo Koopa to a duel, but ultimately lose when the suit is destroyed after a large fall.