Anyone who knows X. J. Kennedy's King Tut--""Tight as a nut/ Keeps his big fat Mummy shut""--will be looking forward to this collection of over fifty bite-sized 'nonsense rhymes. They won't be disappointed. Not with the raunchy perfection of ""Look out, here comes Lucky Sukey/ Sucking on her mucky-looking cookie"" or the wide open exuberance of ""With walloping tails, the whales off Wales/ Whack waves to wicked whitecaps."" The ideas can be as wonderfully wicked as the sounds--""Waking Up Uncle"" confesses, ""My favorite gag/ Is filling Uncle's sleeping bag/ With prune whip yogurt to the brim."" Others are merely intriguing--like the ""Instant Storm"" cooked up from ""frozen French-fried thunder,/ Vanilla-flavored lightning bolts,/ Fresh-frozen raindrop rattle"" or, in a classical vein, ""Medusa's looks had what it takes/ To knock the rust off boilers./ She had a lovely head of snakes,/ She'd put it up in coilers."" David McPhail contributes some leaden imitations of Juniper Tree tableaux, but even these can't weigh down this bright and buoyant accomplishment.