image = underminer.jpg | performer = John Ratzenberger | appear = The Incredibles
- "Behold, the Underminer! I'm always beneath you, but nothing is beneath me! I hereby declare war on peace and happiness! Soon, all will tremble before me!"
- —The Underminer
The Underminer appears at the end of the movie, where he announces his "war on peace and happiness!" The Parr family then put on their masks, ready for battle. This led to such a cliffhanger that the creators of the original Incredibles video game created the sequel, The Incredibles: Rise of the Underminer.
- Brad Bird had stated in the DVD commentary that John Ratzenberger having a part in every film was a Pixar tradition that he was originally not planning to use. However, he did end up giving Ratzenberger a part, with the joke being that his voice is the very last thing viewers hear in the film.
- He appears to have robotic prosthetic hands.