Legend of Eren: Ocarina of Time, where Mikasa is in the role of Link, Bertolt is in the role of Ganondorf, and Eren is in the role of Zelda.
Genderbent Colossal Titan.
Sakura Oogami arm-wrestling Shizuo Heiwajima.
Colossal Titan and Armored Titan get married.
Petra is actually Amy Pond.
What if Attack on Titan got a crossover with Don't hug Me I'm Scared?