It's Little Mac versus differently-coloured Little Mac in these multiplayer screenshots from Punch-Out!! for the Nintendo Wii.
It boggles the mind that in a game with such a great cast of characters, multiplayer is limited to a split-screen battle with Little Mac versus another Little Mac. Nintendo tries to mix things up by making one player transform into Giga Mac when his power bar or whatever fills up, but all in all it looks like a multiplayer mode that's barely more entertaining that Wii Sports Boxing.
For screenies, click here.