During the development of Fantasyland, a Monstro the Whale ride starring the famous aquatic mammal from Pinocchio was proposed. Guests in small boats would enter a cave, perhaps pass by a scenes from the movie with a spashing exit out the whales mouth.
In this design, Montro has taken the place of Hook's pirate ship as the "weenie" in Fantasyland. Casey's track winds along the back of the land. You can almost sense these two attractions beginning to merge.
Of course, now we know Monstro as being then entrance rather than the exit to Storybook Land. The only flaw with the final design is the fact that many children find going INTO a mouth full of teeth just too frightening.
