Mono Mechanic (formerly known as Unigunner) was a medium difficulty stamp in Club Penguin. In order to obtain this stamp, the player had to complete a game of System Defender with only one type of cannon.
This stamp was released on January 14th, 2011, along with other System Defender stamps, as well as the release of the game itself.
In April 2011, it was renamed from "Unigunner" to its current name, "Mono Mechanic".
The best level to earn this stamp on is the first level, with red cannons.