Brawl is on the way. The third installment of Nintendo's mascot-fighting franchise, Super Smash Bros., is coming soon, and the hype train is reaching full steam. Game director Masahiro Sakurai recently began updating a developer's blog at smashbros.com every week day, slowly releasing more and more details about the upcoming game – but it's not enough. Rabid fans want more, and faster, and speculation about the game's still-hidden secrets is running wild.

We're here to embrace the savagery of speculating Smash. Smash It Up! is our new feature series dedicated to the pursuit of educated guesswork, fueled by reader feedback and serving as a springboard to spark new discussions of just what might be in store for us to find once Brawl finally arrives. This time, we're talking characters. But not just pulling up random wishlist choices from any old source – this one's all about the history of cross-overs. Smash Bros. is the ultimate worlds-colliding game, so what other characters have previously interacted with Nintendo's fighter cast in older games? We've picked five solid candidates fitting that criterion, so examine our thoughts below, and then add your own after that.