Voir Professor Balthazar, Season 3 - Episode 13

In Balthazar Town there is an old wooden bridge which is used by the citizens for strolling and enjoying themselves.But night after night the bridge is mysteriously sawn into-and finally falls into the seal. Professor Balthazar discovers the culprit: a large sword-fish. Balthazar invents a magic quick-growing Water-Tree for him, which constantly renews itself and never wears down.