Clad in black-and-white stripes and with an impish gleam in its eye, the baby prowls, ripping Eleanor's poster from the wall and a tablecloth from under Mark's house of cards and causing both sibs to cry, ``Stop that baby.'' Baby howls, Mom comes running, Baby smiles beatifically, and the older kids are blamed and made to clean up. They dream of revenge, but Armstrong's denouement is more poetic. Confined for their apparent misdemeanors, they see the baby go out the cat door and break parole to catch it just before it tumbles down the steps. After it climbs back through the door Mom finally admits that ``That's one speedy crawler.'' Meddaugh catches the children's true-to- life mix of frustration and concern for the baby's safety in witty cartoon-style illustrations. Anyone, child or parent, who's tried to keep up with a rogue infant is sure to chortle at this one. (Picture book. 4-8)