Help with finding 2 words

I need help finding 2 words(my friend said there are only two) that are 2 syllable plural words and when adding "s" to it at the end it becomes a 3 syllable singular word. Any help will be greatly appreciated. Thank you in advance.

[Casiopea]

Originally Posted by jazon720

I need help finding 2 words(my friend said there are only two) that are 2 syllable plural words and when adding "s" to it at the end it becomes a 3 syllable singular word. Any help will be greatly appreciated. Thank you in advance.

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