6. Mario Hoops 3-on-3
Despite his thick waistline, Mario can dominate in any sport he chooses, be it tennis, golf, or basically any Olympic event. His fans are used to him succeeding in every athletic pursuit, so it isn't a stretch for the Mushroom Kingdom to take to the basketball court. However, I'm pretty sure most Final Fantasy players didn't expect their favorite monsters to also join in for a b-ball crossover.
Final Fantasy alums like Moogles, Black Mages, and Cactuars are all playable in Mario Hoops 3-on-3, despite the fact that they all come from a world where basketball doesn't exist. But this incongruous pairing is what happens when Square Enix develops a Mario sports title, despite Square being low on anyone's list of potential sports game devs. The DS release went on to sell 1.5 million copies, which is a little on the low end for Mario spin-offs, no doubt because Final Fantasy diehards weren't as interested in passing the rock as Nintendo had hoped.