Metal Mario is a insanely epic clone of Mario that created itself out of crystal metal a nanosecond after Mario was born. Few people has battled or even saw this figure. They know he lives on a crystal island but it's nearly impossible to get there without years of training. Then the crystal regenerates shortly after and Metal Mario would usually kill you. He has an inability to talk normally, but can use telepathy. He is a near indestructible force only beatable by Undefeatables and some gods.
Defeated by Mario
When Mario was at his full power and had every single item that can benefit him and Metal Mario was in a insanely weak state, Mario ACTUALLY beat Metal Mario believe it or not. He only one by a notch. He got famous for this and many people took pictures of him, 'till they noticed he was a loser again and went all away. At this point, Mario entered a near eternal state of depression as Metal Mario was reformed in a very powerful state.