The Bowl of Milk must be returned to the house in the carrot farm, this is feed the cat in the house and he will be your friend for life and will follow you anywhere. You will need to make the cat like you to return it to the owner.
How to Get the Bowl of Milk
First you need to have the empty bowl of milk from inside the farm house. Then head back on the starting area, enter the Carrot Kings Dinner and you will find a waitress that is carrying a milk. You should have an empty bowl first and ask the waitress to fill your empty bowl. Once filled you have a Bowl of Milk.