Take a look at the sentence again:
Jenny noticed a greasy snail-like trail that snaked from the kitchen counter
onto the floor and then over to the hallway, June, Jenny's
cat, had stolen another stick of butter
and tried to drag it to the laundry room.
Jenny's cat is an appositive. An appositive is a noun phrase that renames the noun that comes before it, in this case, June. An appositive will frequently interrupt the flow of a sentence, and when it does, as in the case above, you need to put a comma both in front and behind the interrupter.
Go back to the sentence to try again.