11) Final Fantasy Origins

Visit Elfheim in the original Final Fantasy, and you’ll likely encounter a gravestone that reads ‘Here Lies Link’, a name that Square probably didn’t randomly pull out of a hat. On the flipside, Super Mario RPG plays host to a generic Final Fantasy beast named ‘Culex’. It’s not straight mockery, mind - Square co-developed it.

12) Halo 3

This is an easter egg that was encountered in both Halo 2 and the Halo 3 beta. Occasionally when a Spartan falls to his doom, he’ll squeak out a familiarly-pitched ‘yahooooo’ - commonly known in Halo circles as the ‘Super Mario Scream’. We don’t know if it’s in the final game, as it appears to be randomly generated.

13) EA Sports Big

Yeah, this was a weird one. EA signed a deal to let them use Mario, Peach and Luigi in their games in 2004, which resulted in the frankly ludicrous sights of Mario and his chums dunking hoops in NBA Street V3 and tearing up the mountains in SSX On Tour. They were about as comfortable a fit in their new environments as Charles Manson and Pol Pot would be in Disneyland.

14)  Soul Calibur II

Each version (PlayStation 2, Xbox and GameCube) of Namco’s Soul Calibur II had its own characters exclusive to its format. There’s nothing strange about it in itself; publishers often employ this tactic to wrench extra money out of their loyal fanbase’s wallets. However, the Cube’s exclusive fighter was none other than Hyrule’s own Link. As a result, Soul Calibur II became the only multi-format release of its generation to sell more copies on Cube than on Xbox/PS2.

15) Metal Gear Solid: Twin Snakes

We’ve covered this one before, so let’s keep it brief; you’ll find figurines of Mario and Yoshi in Otacon’s lab. Shoot ‘em in the mush and you’ll bag yourself a 1UP. Makes sense.