One Piece - episode 6 - 28 Dec, 1999

Still trapped in the cage, Luffy meets a small dog named Chouchou guarding his master's store, despite knowing that his owner is dead. Mohji the Beast Tamer's lion, Ritchie, inadvertently breaks Luffy's cage open, and sends him flying. Chouchou tries to protect the store, but is no match for the much stronger Ritchie, and Mohji burns the store down. Angered by Mohji destroying what the dog finds precious, Luffy mercilessly punches him out. Moved by Luffy's concern for the dog, Nami agrees to work with Luffy for the time being. (Source: Wikipedia) East Blue saga: Orange Town arc: (3/5)