Start with the name a villain from a Superman movie.
Construct a three word sentence, one of the words being the villain's name.
The meaning of the sentence is relevant to the plot of the movie.

Now modify the sentence by adding an 'i' to the name, leaving the other words unchanged. The 'i' is added to the front, middle, or end of the name, but the name is not scrambled.
If read aloud, the modified sentence sounds like a common word (9 letters) used in mathematics.