SMG4: The Other Universe but Dialga, Palkia and Giratina come to help. : r/SMG4

I really hope we get characters from different timelines interacting in Nightmare Time Season 3 : r/StarKid

SMG4 and SMG3 hate each other by Yusaku-Ikeda on DeviantArt

Ropa: Team Galactic

Bowser vs Eggman

Dialga and Palkia battle in SMG1 and SMG2's World. : r/SMG4

Random Character Generator

What villains or antagonists are most memorable for their role in the Pokémon anime series? - Quora

SMG4 Meets The Original Peach by MarkRed345 on DeviantArt

Princess Peach - Super Mario Wiki, the Mario encyclopedia

SMG4: The Other Universe, The SMG4/GLITCH Wiki