Eight-year-old Thaddeus is jealous of his new baby sister, Maddie, and wants nothing to do with her until he realizes she’s a gateway for an alien invasion. His first clue: her single syllable babble (“ga”) is always vocalized in strings of prime numbers. When the aliens finally emerge—from small pods that Maddie throws up—they turn out to be “missionaries of smiles and happy feelings.” This is a deep disappointment to Thaddeus. Meanwhile, the government locks Maddie away. Thaddeus is more than willing to exploit his parents’ resulting distress for personal gain. But then he recognizes the look on his sister’s face in her isolation room as one all too familiar to him: loneliness. First published in the New York Times Magazine, Gene Luen Yang’s smart, funny graphic novel is hilarious from its first page (“my mother’s womb is a Trojan horse”) to its last. Smiles and happy feelings indeed. (Age 9 and older)