Gustave was a man who originally made his living as an animal-trainer, and who could have made a living for himself indefinitely performing at circuses worldwide. However, he became inordinately greedy, and decided that he could do better by training animals to commit crimes for him. He began to do so, and when the police began to pursue him, he fled in a motorboat, heading out to sea. This allowed Aquaman to enter the chase, and although he was not able to capture Gustave, he and his fellow sea creatures did damage the boat enough to allow the Coast Guard to catch up to it. Aquaman himself was forced to break off the chase to handle another emergency.