The theme song had a different line ending in the "Ay-nee" sound effect depending on the episode. Later episodes of the show also had "We pay tons of income tax" in place of "While Bill Clinton plays the sax", and "Meet Ralph and Dr. Scratchn Sniff, say hi to Hello Nurse" in place of "Meet Pinky and the Brain who want to rule the universe".
Examples: What is or isn't?
Removed:
These are Couch Gag and Evolving Credits respectively.
Declined during YKTTW process: Several Anime Examples that are either Anime Theme Song or Theme Song Cameo or Theme and Variations