6. Money Mayweather & Iron Mike (SmackDown Vs. Raw 2009/WWE 13)
Floyd Mayweather worked a surprisingly good boxer vs. wrestler match with Big Show at WrestleMania XXIV in 2008. The match was so well-received in fact that THQ wanted to digitalise Mayweather for use in their upcoming SmackDown vs. Raw 2009 title. Talks progressed well, then lil' Floyd pulled out of negotiations.
The problem here was that developers had already created code for his entrance, move set and animations. Now, they had no purpose, and it didn't look like they ever would. Years later, when the team were working on WWE 13, Mike Tyson signed on to become a bonus character in the game.
'Iron' Mike saved the day.
Reportedly, according to TheGamer.com, Tyson's in-game model was animated with scraps left over from the Mayweather code. In effect, THQ swapped one boxer out for another, adjusted the height of the model and ran with it. His entrance and moves were the exact same.