Lois is confused by her "son's" behavior.
Lois Stevenson is a human who appears in the episode Baby It's You. She is the mother of an unnamed human baby, but because of a mix-up at the hospital, she was mistakenly given Bomble, a baby monster, while her actual son was accidentally taken by Ickis, Krumm, and Oblina, who attempted to switch them back. Although Lois and Bomble are entirely unrelated, she still believed he was her son and took him home with her and her husband Stan. When he first arrived, Bomble caused lots of destruction in the house, such as ripping a banner, tearing the couch apart, and shattering a window. Due to the damage caused, Lois and Stan decided to put him in a cage.
She and Stan also got their parents to come to the house to meet their "grandson", finding him scary at first, but still cute. When the trio came to the house to switch the human baby (without being seen by them), Krumm releaed his stench around the living room, which makes Lois think Bomble needs his diaper changed. Deciding to do it, she takes the small monster out of his cage, and take him upstairs. The trio took this chance to switch the babies back. Lois put Bomble on a changing table while she puts on a hazmat suit. The trio quickly switch Bomble with the human infant, and then escape. Lois comes back and is delighted to meet her real son, and quickly goes downstairs to show Stan.
At the end of the episode, Lois and Stan play with their new son, until he scares them with a creepy face, causing them to fall down in shock, while the baby laughs cutely.