Modders are like modern-day magicians. They can combine two separate games and create one ostensibly cohesive world, even if it's for a small sliver of gameplay or (more likely) a short YouTube clip. Modder BigSharkZ combined The Legend of Zelda: The Wind Waker with a portion of The Legend of Zelda: Ocarina of Time, to wonderful effect.
It took BigSharkZ two weeks to combine the two titles the result ended up including, "Link’s model as well as his items and some animations, Aryll into Saria, Mila into Malon, with multiple custom maps and other model changes, even a custom Navi actor!"
🎥: BigSharkZ from YouTube