The characters having different tongue colors comes from an experience Danny Antonucci once had. While in a meeting, his son and friends came in, and due to all the candy they just ate, they had different tongue colors.
This was the last major animated TV series to use conventional cel animation. When it was renewed after the fourth season, the studio switched to digital ink-and-paint and compositing.
There is no given time line for the show. Danny Antonucci has stated that he wanted the show to appeal to any generation.
This was Cartoon Network's longest-running series at the time it ended in 2009. It held the record for 15 years until surpassed by Teen Titans Go! (2013) in 2024.
Danny Antonucci, previously known for his adult-oriented, highly disturbing animated shorts, created this series on a dare as a show that kids could watch.