Den Den Mushi are unique, snail-like creatures in One Piece used for communication across the seas, and they play a key role in the world of the Straw Hat Pirates.

As the cook of the Straw Hat Pirates, Sanji frequently uses Den Den Mushi to communicate with his crew, especially during their adventures across the Grand Line.

Den Den Mushi come in various forms, including:

• Transponder Snails for voice communication

• Visual Den Den Mushi for both audio and video communication

These snails are vital in maintaining communication between the crew and other characters or organizations across vast distances.

Sanji, known for his sometimes humorous interactions with these devices, often uses Den Den Mushi in situations involving missions, updates, or to deliver his signature flirting with women through the telephone.

Sanji‘s interactions with Den Den Mushi also provide many comedic moments in the series, particularly due to his character’s charisma and often over-the-top flirtations.

Den Den Mushi are not just important for the Straw Hat Pirates, but also for various other characters, including the Marines, World Government, and other pirates. They are used for critical communications that advance the story.