However, it's important to note that the show was actually produced in three different phases:
* Nickelodeon: Seasons 1-3 (1991-1995)
* Spumco: Season 4 (1996) - After a conflict with Nickelodeon, creators John Kricfalusi and Bob Camp created their own version of the show, but it didn't last long.
* Nickelodeon: Season 5 (1996-1996) - Nickelodeon attempted to revive the show, but it was significantly different in tone and quality, and was canceled after only 13 episodes.
So, while there are technically 5 seasons, the show experienced a major change in quality and direction between the original Nickelodeon run and the later seasons.