In The Alien in My Mom's Belly, Zach is an aspiring astronaut who knows everything about space-like how astronauts grow taller and sunsets on Mars are blue. But when strange things start happening at home, like his mom turning green and eating bizarre foods, Zach is convinced there's an alien growing in her belly. With a serious "astronaut voice," he reveals his discovery to his parents, only to learn that it's not an alien, but a baby. As his mom's belly grows, Zach prepares in his own quirky way-making forts with "no aliens allowed" signs and wearing a tin foil hat. On the big day, Zach rushes to the hospital, dressed as an astronaut, and is amazed to meet his new baby sister, who is definitely not the green, slimy alien he imagined. This playful and heartwarming story captures the excitement and wonder of becoming a big brother with charming illustrations that bring Zach's imaginative journey to life.