One Piece S02E70 - The First Patient! Anecdote of the Rumble Ball

After their adventures in Arabasta, the crew come upon another deserted island and split up tasks amongst themselves. Chopper is left in charge of guarding the ship, and he reminisces about the day he first made the rumble ball and his first patient, Dr. Kureha, while spending some time with the newest crewmember: Nico Robin.