This phrase, "My hovercraft is full of eels" is a humorous comment attributed to Douglas Adams, British author and humorist. It's from his science fiction novel, "The Hitchhiker's Guide to the Galaxy". The context in which it appears suggests that the speaker has misused their hovercraft as a fish tank or transport for aquatic creatures. It's often used when someone is faced with an unexpected situation or when a conversation takes an unusual turn.