The Were-Rat is one of the undead pets and a major antagonist of Frankenweenie (2012) film. The Were-Rat was a dead rat that Edgar E Gore found inside a garbage can so he can use it as an experiment to reanimate the dead rat to come back to life at the science classroom, however his experiment went wrong when the lightning strikes the dead rat and it mutates into a slightly larger, more vicious Lycanthropic creature. When Edgar scrams out of the class and out of school screaming, the Gym Teacher investigates the noise and tries to find out what was going on. When she went to the science classroom and looks inside at first there is nothing there, but the Were-Rat suddenly pops up and snarls at the Gym Teacher.
At the Dutch day festival, The Gym Teacher was chased by a hideous Creature hopping after her to attack, however it then turned its attention back to Edgar after he bumps into it after being chased by Bob's mutant Sea-Monkeys. After that the Were-rat is seen approaching to Elsa, Persephone while Edgar cowered behind them, however Sparky stops the Were-Rat in its tracks and the two fight, after the Were-Rat throws Sparky to the side he tries to take a bite out of him, only to chomp onto Sparky's neckbolt and get electrocuted, thus reverting him back into the dead piece of roadkill he once was.