Mirror Team Rocket showed up in "The Cave of Mirrors!" as the good-guy versions of everyone's favorite villains. They're basically what Team Rocket would be if they weren't, well, terrible people—these guys are actual heroes who go after criminals and bad guys instead of stealing Pokémon all day.
The weird thing about them is how opposite their personalities are to the originals. They've also got noticeably deeper voices, which makes them sound pretty intimidating compared to the regular Team Rocket crew. Even their uniforms tip you off that something's different—their "R" insignia is flipped horizontally instead of facing the normal way.
Since they only appear in that one episode, they're pretty minor characters overall, but fans find the whole mirror-universe-heroes angle pretty fun.
Content compiled by AnimeList.moe from publicly available sources.
