for Saving the Whole Wide World by Judd Winick
HILO is just settling into life on earth (Bowling? Knock-knock jokes? OUTSTANDING!) when strange portals begin opening up all over town. And HOLY MACKEREL! Even STRANGER creatures are coming through them! But it will take more than a GIANT MUTANT CHICKEN, A VIKING HIPPO, A MAGICAL WARRIOR CAT, or even a few MILLION KILLER VEGETABLES to stop Team Hilo ... er, WON'T IT? Can Hilo, DJ, and Gina figure out how to send these creatures back to their worlds before they DESTROY the earth?
Publisher description retrieved from Google Books.