"Stupid Sidekick Union" is the second episode of Season 5.
The sidekick union is going on a massive strike, since Stimpy can't stand the abusive slaps Ren does to him anymore. So Ren is forced to audition new sidekicks, but no one seems to be able to pull out the same pranks as Stimpy.
- Despite being a Season 5 episode, Ol' Blue Nose and this episode aired two weeks before the last two Season 4 episodes did (Superstitious Stimpy and Travelogue).
- This episode is Tom McGrath's directional debut.
- This is one of the rare episodes where Stimpy takes a dislike to his best friend, Ren, so this is the only episode where Stimpy takes a dislike to Ren for something he did.
- This episode signals the fact that Ren and Stimpy is a cartoon as this is an episode focusing and parodying on the duo's own show, created by John Kricfalusi.