Who win, though.

I'll be the roundabout~

...ok hear me out, when kirby suck things up it goes inside kirby. Then when Mario does that Cappy thing to a Thing, Mario goes in to the thing and controls the thing.

So basiclly Mario wins here as long Cappy hits Kirbys head, that will happen due to the fact Kirby will expand for copy Mario and get Mario's abillitis.

...Thing is Mario inside Kirby's body Who is basiclly Mario, So inconlusion, Mario (Jumpman) Mario became Mario Mario Mario and pinker.