Joanna

Joanna is the secondary antagonist and the pet lizard of McLeach in The Rescuers Down Under. She provides a more comical role than her psychotic master but is nevertheless a disobedient and greedy reptile with a particular fondness of eggs.

Joanna is incapable of speech but is very expressive and intelligent - despite this she often receives violent treatment from McLeach, who she is visibly afraid of but who she also seeks to please.

Joanna is a Goanna Lizard and is quite predatory, as stated above she especially loves eggs and was used by McLeach to try and eat the eggs of an incredibly rare eagle - however Joanna was unable to eat the eggs as they were actually rocks made to disguise the real eggs, which Bernard hid from her. So instead, Joanna simply tried to toss them away (though they all survived regardless).

Joanna, although intelligent, was quick to attack smaller prey and this would prove to be her downfall when Bernard tricked her into chasing him during the climax of the film - causing her to accidentally charge into McLeach and plunge into the river with her master. Joanna is seen defeated when Bernard tricks her!

Unlike McLeach, Joanna managed to escape the river and was even seen waving goodbye to her master's moments before he fell to his death off the waterfall. It is unknown what happened to Joanna after that.

Trivia

 * McLeach is the second villain to own a reptilian minion as Madame Medusa had a pair of crocodiles in the first film.