Scales of Justice
The Scales of Justice are large weighing scales used in Judge Koopa's courtroom to determine how many years convicted criminals are to serve at Koopatraz State Prison. They are normally concealed behind a secret panel, and are only revealed when needed. They were only ever used in The Super Mario Bros. Super Show! episode "Escape from Koopatraz".
The Scales of Justice are apparently rigged, as when Mario was placed onto one of the scales, it registered his weight at five-hundred pounds, the highest reading it could display, then lit up. Judge Koopa then took Mario's weight and converted it to years, deeming that he, along with Luigi, Princess Toadstool and Toad would serve a five-hundred year sentence at Koopatraz State Prison.
Nothing else is known about the Scales of Justice, as they were only seen during that one instance.