Two words that are quite similar in singular form are have very different plural forms.
Example:
The plural of House = Houses, but the plural of Mouse = Mice.
So, by applying the "wrong" form change, can you make silly plurals?
Example:
If the plural of Goose = Geese, would the plural of Moose = Meese?
You can even take it a step further...as from above,
If the plural of Mouse is Mice, would the plural of Spouse = Spice?
Hmmm...