To be clear, this isn't a Mega evolved version of Bidoof, although it should be. It's just a meme that was created by That Splicing Adventure; Bidoof mashed with every (other?) legendary in the Pokemon games. Glorious, yes, but probably not something Game Freak would ever make a reality. Unfortunately!
Still, now that we know what the deal with Mega Pokemon are—temporary evolutions that are kind of like power-ups, as they can only happen in-battle—one can't help but think of the possibilities when it comes to Mega Pokemon. Aside from the few that have been revealed—Mewtwo, Absol, Blaziken, Lucario, Ampharos—who else could use a mega evolution? Immediately we'll think of silly Pokemon, like Bidoof, sure. Who else?