The Boxing Ring is Little Mac's home stage in Super Smash Bros for Wii U and 3DS. Unlike most stages belonging to new series characters, the Boxing Ring was actually revealed at E3 2013, half a year before Little Mac was revealed to be playable. They hid this by making a Smash Bros version of the boxing ring, for some reason. The Boxing Ring is, well, a boxing ring. It's got some platforms out of the boxing ring for fighters to stand on, but that unfortunately means that the stage has walkoffs. Goodbye, tournament legality. The stage is also home to the Boxing Ring Lights, who is unfortunately not a character.
Now, the Boxing Ring is nice and all, but it does pose a problem. There aren't exactly many locales from Punch-Out to make a stage from, so if there's a Smash 5, what is the new Punch-Out stage going to be? (Unless they pull an Ice Climbers and cut him). I guess they could make the jogging section a stage, with Doc Louis stealing the fighter's bikes.
Oh yeah, in the Wii U version, the Boxing Ring screen gives all of the fighters boxing ring aliases, for example, Mr. Game and Watch is the Master of Two Dimensions, and Little Mac is the Bruiser from the Bronx. Unfortunately, Luigi isn't called the King of Second Bananas. YOU HAD ONE JOB, SAMURAI.!!! REEEEEEEEEEEEE!!!