Monstro is a predatory sperm whale who is one of the main villains from Pinocchio. While Pinocchio spends the night in Stromboli's troupe and, later, Pleasure Island, Gepetto searches for his son. Taken to sea, the toymaker, Figaro and Cleo are swallowed whole (complete with a boat) by Monstro. The whale later swallows Pinocchio, when the little wooden boy comes searching for his father. Monstro has a reputation as a "whale of a whale" and is feared by all the creatures of the sea, and apparently on land, as even Jiminy knew of him and of his deeds. Normally, Monstro, being a sperm whale, eats and battles giant squid for fun, but he also hates humans for hunting his species for spermaceti.
Joe Grant's Character Model Department was responsible for the design of Monstro the whale. Models were constructed both of Monstro himself and of his belly, complete with skeleton. In addition, inspirational sketch artist Gustaf Tenggren created a watercolour of Gepetto in Monstro's belly.
The animation of Monstro was originally to be assigned to Vladimir Tytla (animator of Doc, Grumpy, Stromboli, and, later, Yensid, Chernabog, Dumbo, and Friend Owl), but, perhaps out of worry that Tytla might get carried away, Disney eventually assigned Wolfgang Reitherman to the task. He animated Monstro as a cunning creature with a brain, making his pursuit of his prey all the more frightening. To Reitherman can also be attributed, to an extent, the timing and staging of Monstro's chase sequences, which were timed to suggest the whale's great weight and power. Reitherman drew a set of sketches for a discarded sequence showing Monstro consuming Gepetto's boat; Monstro was to emerge suddenly on the otherwise serene sea scene, first looking like a large mound before revealing his teeth and swallowing the boat in one movement before disappearing underwater once more.
Monstro is first mentioned in the film when Pinocchio and Jiminy Cricket receive a message from the Blue Fairy that the whale has swallowed Gepetto, Figaro and Cleo when the toymaker took to sea to rescue Pinocchio from Pleasure Island. The three are still alive, inside Monstro's belly. Against Jiminy's warnings, Pinocchio resolves to find and rescue Gepetto. Though Jiminy tries to dissuade Pinocchio, warning that Monstro is "a whale of a whale... he swallows ships whole!", he does not hesitate to join the wooden boy in his search at the bottom of the sea. The two search for Monstro; mention of the whale's name causes the sea creatures to flee in terror. Meanwhile, in Monstro's belly, Gepetto and Figaro are trying to catch fish to eat. The toymaker tells Figaro that he fears that they will starve in the belly of the sleeping whale.
Monstro wakes at the sight of a school of tuna swimming nearby. Opening his great eyes, the whale pursues the fish, mouth open, tearing through the ocean. When Pinocchio sees Monstro approaching, he flees for his life, pushing past the tuna, though he is nevertheless consumed by the beast. The sprightly Jiminy escapes the creature's jaws, but, on discovery that Pinocchio has been swallowed, tries to enter Monstro's now closed mouth. Inside the whale's belly, Pinocchio, reunited with his father, proposes that they escape in a raft (constructed by Gepetto) when Monstro opens his mouth. When told that "everything comes in... nothing goes out" of Monstro's jaws, the wooden boy suggests that they start a fire to make the whale sneeze.
Monstro once again opens his eyes, this time to find smoke rising from his blowhole. He begins taking deep breaths; while his mouth is open, Pinocchio, Gepetto and the pets try to escape; they succeed when Monstro finally sneezes, sending them flying out to the sea. After another powerful sneeze, an enraged Monstro pursues the raft while Pinocchio and Gepetto row for their lives. Monstro dives underwater and emerges underneath the raft; Pinoccho and his father row away in time, but when Monstro leaps after them, they are forced to jump into the sea. The whale smashes the raft into pieces with his tail. Pinocchio saves his father from drowning and pulls him to shore, with Monstro in hot pursuit. As the whale builds up speed, the waves drifting from the cliffs of the shore hinder Pinocchio. Monstro leaps into the air, aiming to consume and kill the two. Finally, paddling madly, the wooden boy swims through the hole in the cliffs just as Monstro smashes into a giant cliff, the impact of which sends Pinocchio and Gepetto flying onto the beach. As the toymaker comes to, Jiminy, Figaro and Cleo are washed onto the shore. Pinocchio, however, didn't survive the blow. The puppet is later revived, and turned into a real boy, by the Blue Fairy.
Role in the series
Monstro reprises his role from the film, but it is also inside the whale where Spyro and Sora discover Fagin has recently been eaten by the whale as well. Fagin offers to help the Lodgers so he can get close to Pinocchio. He manages to catch him, and imprisons him in the Parasite Cage. The Lodgers and Sora manage to defeat the cage, whereas Pinocchio ends up losing his heart. Fagin's Riku clone, Repliku, takes the heartless Pinocchio, and they go into Monstro's stomach. Then after the last battle with the strengthened Parasite Cage, Fagin made his escape until the next day, the Lodgers and Sora escape Monstro for the true final battle of the movie.
In Disney Villains' Revenge, the Coachman is able to destroy the happy ending of Pinocchio, allowing him to expand his operations on Pleasure Island to the rest of Italy. As a safety measure to make sure no one escapes the freakshow circus, the Coachman placed a mind-control amulet on Monstro the Whale to turn him into his guard beast, swallowing any potential escapee who tries to flee by sea travel. Spongebob is able to destroy the amulet controlling Monstro, allowing the whale to regain its mind and swim off to parts unknown. Sora and Riku later use Monstro to help them destroy the Freakshow Ringmaster by crashing into the monster, wounding it long enough for them to destroy it for good.... Seemingly.
As reveiled in the cronicles series, it appears that the Leage was finally done with Monstro and desided to free the creature from their services, feeling that it's clear not even the whale of a whale is not a match to the lougers. It ended up becoming a momentary prison for The Devious Puppet after his defeat.