Fans of Ada Twist, Scientist will want to join Dr. Cosmic's class of clever monsters as they explore the dark depths of the ocean in the fourth book of the Mad Scientist Academy series. The students in Dr. Cosmic's class take their lessons underwater when they're introduced to his latest invention, the SKWID--a special submarine that explores the ocean and looks like a real giant squid! With the guidance of oceanographer Professor Fathom, the class embarks on an exploration of the deep sea. Their next assignment? Identify the smallest producers and consumers of the ocean. But when a giant whale approaches the SKWID, mistaking it for an actual squid, the students must use their trusted scientific handbooks to find a way to escape the submarine and return to the undersea lab--before they become the whale's lunch!