Or maybe it should be "Attack on Ketchum"
Unsurprisingly, none of my son's second grade classmates are familiar with the "Attack on Titan" series, but Pikachu is always good.
"Attack on Titan" and "Pokemon" seemed like good candidates for a mashup as they are both manga and anime series that engage in serious violations of the law of conservation of mass. The Titans, including the "Colossal Titan," who looms so compellingly over the barrier wall, spring instantaneously from normal sized humans.
And Pokemon somehow fit in those little balls.