Every Decade has Opposites!
Every Decade has an Opposite Counterpart!
1920s: Dr Jekyll and Mr Hyde
1930s: Mickey Mouse and Ha Cha Cha Mortimer Mouse who was created in 1936
1940s: Buggs Bunny and Daffy Duck.
1950s: Superman and Bizzaro, while Superman was made Earlier, Bizzaro made his first appearance in 1958
1960s: Batman and Owlman who is an evil alternate Universe version of Batman who was first intruded in 1964
1970s: Scooby Doo and Scrappy Doo
1980s: Spider-Man and Venom, While Spidey was made earlier, Venom was Introduced in the 80s
1990s: Mario and Wario, Wario was First Introduced in 1992 in Super Mario Land 2
2000s: Sonic and Shadow the Hedgehog, this Opposite Duo was first introduced in 2001 in Sonic Adventure 2
2010s: Frisk and Chara from Undertale.
2020s: Pim and Charlie vs Grim and Gnarly from Smiling Friends