Ep 13. Takes A Dive

When it is revealed that one of Ms. Frizzle's ancestors was a famous pirate, Wanda decides to convince Ms. Frizzle to try to find the treasure that her ancestor left behind. Ms. Frizzle agrees and the children head off on a treasure hunt, though in order to get down to the ocean floor, Ms. Frizzle transforms the students into various aquatic animals. However, they soon realize that they'll have to rely on one another and many of the existing plants and animals in the ocean's depths if they wish to survive long enough to even come close to the old pirate ship.