In "No Children Allowed" (Episode 57), the Ricardo's neighbor, Mrs. Trumbull (played by Elizabeth Patterson) complains to the Mertzes about Little Ricky's all night crying and points out that her lease clearly states there are to be no children in the building. Eventually a big fight erupts between the Mertzes and Ricardos and Little Ricky is inadvertently left alone in the apartment. Realizing their mistake, the foursome rush back to find Little Ricky in Mrs. Trumbull's arms. From this episode on, she is the Ricardo's reliable babysitter.