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.
Had stolen another stick of butter is one item in a series of two. Tried to drag it to the laundry room is the second item in the series. When you have only two items in a series—and they are not main clauses—a coordinating conjunction like and is all that you need to join them.
Go back to the sentence to try again.