From the Super Mario Wiki, the Mario encyclopedia

Mike (nickname The Mike-inator)

I is just your everyday kid who likes videogames. I am highly determined to be the best at all videogames. I was the best at most of the vgs I brought. Plus, I even went down the Pit of 100 Trials about, like I dunno, 10 times in Paper Mario 2, right after I slayed Bonetail! Took me a lot of training if I was ever gonna beat Bonetail and win the Return Postage Badge, and as proof of my defeating Bonetail, I got his name on the Tattle Log as well as my getting the Return Postage Badge. Whatever Badges I get in an RPG VG, I wanna keep!