Here are many forms of the word cricket. I've included non-possessive forms and possessive forms to show you how similar these words are, but the difference between these four forms is crucial.
one single cricket
more than one cricket/multiple crickets
belonging to one single cricket
belonging to more than one cricket/multiple crickets
Here's an example of how the plural possessive form of cricket could be used in a sentence:
If you walk by the pond at night, you'll hear all the crickets' legs rubbing together, creating a chirping noise.
Putting the apostrophe (') at the end of the plural non-possessive form shows that an object or objects belongs to multiple crickets.