The Evil Ocean was an ocean monster that appeared in the form of a huge wave. The only notable feature of the Evil Ocean is that it has an evil looking face; otherwise, it looks just like a normal wave. In a flashback in the episode "His Hero," the Evil Ocean was destroyed by Billy, so it's unlikely to have another appearance. Its face is similar to the face of the Fear Feaster . The Evil Ocean appears to be a tidal wave, since even Billy was shorter than it.