Tramp: What's wrong, Pidge? Lady: A rat! Tramp: Where? Lady: Upstairs! In the baby's room!
~ Lady informing Tramp of the danger.
The Rat is the final antagonist in Disney's 15th full-length animated feature film Lady and the Tramp. It is a vicious and violent rat that plans to break into the family house and attack their newborn baby.
Lady first encounters the rat one day in her yard. The rat tries to creep into the house, but Lady growls and chases it away, escaping through a hole in the fence.
The rat later appears in the climax of the film. Either seeking revenge for Lady chasing it away or simply desiring to attack the humans, the rat emerges from the hole in the fence that it was chased into earlier. It watches Tramp walk away after an argument between Lady and he, then proceeds to make its way to the house.
Lady (who is chained to her doghouse) sees the mysterious rat sneaking through a pile of logs. Lady comes out growling and barking to confront it, but the rat stays out of her reach and runs up onto the ivy growing on the house, giving Lady a taunting stare before climbing up to the gutter. Lady continues to bark, attempting to warn of the rat. However, Aunt Sarah simply shushes her and yells at her. Taking advantage of Sarah being distracted, the rat makes its way into the baby's room through an open window. Tramp hears Lady's barking and asks what is wrong, and Lady informs him of the rat. She tells him how to get into the house, so he can go save the baby.
Tramp enters the house and makes his way to the baby's room, seeing the rat lurking under the furniture, hissing, illuminated only by the flashes of lightning outside. As Tramp approaches, the rat makes a sudden dash for the baby's cradle, to which Tramp gives chase. He diverts the rat away from the crib and chases it back under the furniture, then back out again. With nowhere to run, the rat turns and attacks Tramp, clawing and biting while also jumping on his back. Tramp manages to throw it off and even briefly bite it, but the rat keeps fighting.
The rat jumps on the furniture, causing Tramp to chase it again, knocking over housewares and causing a mess. It leads Tramp back under the furniture, getting Tramp temporarily stuck. As Tramp frees himself, the rat runs over to the cradle and sneers at Tramp. Lady comes in as Tramp frees himself. The rat prepares to jump into the cradle and kill the baby, but Tramp jumps up just before the rat makes it inside and grabs it out of the air, knocking the cradle over and waking up the baby in the process.
As Lady rushes over to check on the crying baby, the rat runs from Tramp, who catches up to it and traps it behind a chair. The two then engage in a violent fight of clawing and biting, knocking over more items and tearing down the curtains. Though the battle is vicious, Tramp emerges victorious, killing the rat with only minor damage to his left front paw.
However, Aunt Sarah comes in and, misunderstanding the situation, thinks Tramp attacked the baby. She has the dogcatcher come to pick him up, and locks Lady in the basement, though Lady is desperately trying to show her the rat's corpse to prove his innocence. Luckily, Lady's owners arrive back home and let her free, and she shows them the rat, clearing Tramp's name. Aunt Sarah screams "A Rat!" when she sees the rat's dead body. Tramp is later rescued, and becomes a member of the family as thanks for killing the homicidal vermin.
Despite being mysterious and quiet, the rat shows an extremely violent and destructive nature, wishing to kill and destroy. It openly antagonizes the dogs, even taunting and sneering at them on occasion. Though its reasons as to why it wants to kill the baby are unknown, some suggestions have arisen such as revenge for Lady chasing it off, a desire to eat the baby, rabies, some other malignant disease, or simply an innate desire to kill. It shows intelligence beyond a simply hungry and carnivorous predator; it is extremely crafty, homicidal and manipulative with sinister intentions and goals.
The rat has gray and black fur. It has sharp teeth and claws, as well as two slanted, glowing yellow eyes. It also has a long pink tail, two small ears, and long whiskers. It is slim, yet extremely large, comparable in size to a small dog and even able to easily fight with larger animals.
In early drafts, the rat was intended to be more anthropomorphic and be named "Herman". He was even intended to go up against Si and Am. However, this idea was scrapped for unknown reasons, and the rat in the final product had no confirmed name or gender.
Also in early drafts, it was Lady that was supposed to fight and kill Herman, not Tramp.
The rat was animated by the late Wolfgang Reitherman, who also animated Monstro in Pinocchio.
The rat is one of the two characters in Lady and the Tramp to die, and the only antagonist to die. The other death was one of the dogs in the pound being put down off-screen.
The first scene of Lady chasing the rat is not included in many book versions.
The rat and the fight scene with Tramp has been considered scary and violent by some, stating it as a sudden dark moment in an otherwise lighthearted film.
The rat's gender is unclear, perhaps male since it was named Herman in the early script.
The rat makes a cameo appearance in the Disneyland TV episode "The Great Cat Family".