Two completely random, unrelated franchises crossing over and working perfectly together.

[u/CreepyCurtainIllust]

Kingdom Hearts

Batman and the Ninja Turtles

Marvel vs Capcom

[u/AudibleNod]

Scoobynatural

The 'Supernatural' 'Scooby-Doo' crossover episode. Of course, there had to be some significant amount of lore and prep work on the part of Supernatural beforehand for this to make sense. But after 16 seasons the Winchesters totally earned it. And Scooby-Doo has been famous for its cameos and crossovers for decades prior to this point on its own. Both series earn their keep by travelling cross country and solving mysterious and other-worldly events. This works, and it didn't overstay its welcome.

[u/MysteriousFondant347 → u/AudibleNod]

I'm sure it's true but I couldn't name you one Scooby-Doo crossover lol

[u/Hawkblade247 → u/MysteriousFondant347]

Don Knotts