Never Babysit the Hippopotamuses!

Johnson debuts with a comic cautionary tale that wryly catalogues the eminently sensible reasons not to spend a night caring for brother and sister pachyderms. ``Don't play leapfrog with them, they can be hard to jump over,'' the narrator prudently cautions. ``Bathtime is crazy. The Hippos love to do cannonballs into the tub.'' As the night wears on, the outsize charges continue to wreak havoc on the house--and on their battle-weary sitter--with a variety of escapades that unfold in a deadpan recital punctuated by an ever-more anxious refrain, ``Oh, never, ever babysit the Hippopotamuses!'' Johnson wraps up the book with a punchline that makes a night chez Hippo look like a cakewalk--never baby-sit the Hippopotamuses ``unless, of course, your only other choice is to babysit their neighbors, the Monkeys!'' Carter's (the Spurwink Gang books) watercolors, with their wriggling ink lines and vivid greens and violets, generate the requisite level of manic energy. Ages 4-7. (Oct.)