I'd like it if you write a short story about a woman who goes on a trip to the grocery store for milk. Please make less than 200 words and create a surprise at the ending.
Maria looked in the refrigerator and sighed when she saw that the family had run out of milk again. She knew that her kids needed milk for breakfast in the morning, and if she didn't go to the store right away, it would cause a big problem for everyone. She looked around the house and found her keys and her wallet before heading out the door. 

When Maria pulled up to the front of the store she was shocked to see that the lights were on but no one was in the building. She walked carefully through the deserted aisles, looking for clues about where everyone had gone. All of a sudden, she heard movement behind her. She turned around quickly, prepared to fight. 

But instead of finding a person behind her, she saw a big milk cow standing in the middle of the cereal aisle. The cow mooed loudly. 

Maria sighed again. I might as well take this cow home, she thought to herself. After all, if the family had a milk cow, they would never run out of milk again. 