+8 Mario vs. Bowser
+7 Kirby vs. Meta Knight
+6 Sonic vs. Dr. Robotnik
+5 Ike vs. Black Knight
+4 Jill Valentine vs. Nemesis
+3 Jim vs. Queen Slug-for-a-Butt
+2 Conker vs. Great Mighty Poo
+1 Katherine vs. Catherine
Top two are legitimate rivalries. Bottom two don't even come remotely close to qualifying. Conker fought the Great Mighty Poo once, he was a boss fight. How that even comes close to being a rivalry is beyond me.
Katherine vs. Catherine is even more confounding, they only even INTERACT once in the entire game, you can't be someone's true rival if you don't even know they exist.
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Falcon Punch
http://www.youtube.com/watch?v=FFtw7qW7Vcw