In every Rampage game, Lizzie, along with George and Ralph, are typically mutated into monsters through experiments conducted at Scumlabs (or any other science-related quandary). These experiments go horribly wrong and transform them into giant monsters. This is the generic origin for most monsters that appear in the Rampage franchise. However it differs slightly in each game:
In Rampage (1986), Lizzie was a woman who became mutated while swimming in a lake by discarded radioactive waste, turning into a giant lizard/dinosaur as a result. Coincidentally, George and Ralph also became mutated into giant monsters. They all saw each other as alike in every way, rather than monstrous abhorrences that normal humans saw them to be. Throughout the game the trio begin to desolate every high-rise city, destroying buildings, gorge civilians, smash vehicles and eradicate offensive military forces which stood in their wake of destruction until they reach Plano, Illinois, the final level of the game.
Lizzie is the only monster able to eat men. Lizzie cannot eat any other human other than men.
In Rampage: World Tour (1997), Lizzie's origin is in fact asymmetrical to her origin in Rampage (1986). This time, she is a scientist working at a Scumlabs facility until an explosion occurred, mutating her into a giant sized lizard. Lizzie, George, and Ralph, mutated by the blast, travel the world to destroy all of Scumlab's bases and all of the Scumlabs employees.
At the end of the game, the last Scumlabs employee, Dr. Elizabeth Veronica, tries to eliminate Lizzie with a ray gun, only to have shrunk Lizzie and her friends, ending up inside Dr Elizabeth Veronica's ship.
In Rampage 2: Universal Tour (1999), Lizzie (along with George and Ralph) are unplayable at the beginning of the game, as they are all imprisoned in heavy duty cages for the whole world to see. This is because Dr Elizabeth Veronica captured them once they were tiny. They are in New York City, London and Lizzie was held captive in Tokyo. She awaits for her rescue when the newer monsters Boris, Curtis and Ruby are created from another explosion created during an experiment in a new lab in Salt Lake City.
Once Lizzie's cage has been smashed open, she is unlocked as a playable monster. The code to play as Lizzie is 'S4VRS'.
After Lizzie, George and Ralph have been freed, they are all playable during the invasion of the aliens when they attempt to conquer the Earth.
In Rampage Through Time (2000), Lizzie returns to Earth after having dealt with the alien invasion aftermath, smashing straight through the roof of the building housing the time machine and hopping in. She then immediately dashes towards the time machine, entering through the portal that opened up.
She and the rest of the monsters then begin to terrorize the past, present and future, thus creating a disruption through important events in history, messing up the time stream.
In Rampage: Puzzle Attack (2001), Lizzie will occasionally climb the side of the bin the player is dropping blocks in and jump into the bin if the player has achieved a specific goal or objective.
In Rescue Mode, sometimes Lizzie is imprisoned in a huge metal cage at the bottom of the screen until the player frees her by removing all the blocks on top of his cage before time runs out.
In Rampage: Total Destruction (2006), Lizzie was a sexy woman who drank some Scum Soda causing her to have a violent reaction transforming her into a giant lizard and making her clothes rip. She is one of the 6 initially playable monsters that broke out of her Cryo-Tube, along with George, Ralph, Rhett, Ramsey and Gilman.
At the end of the game, when Lizzie reaches the final Scum Soda base in New York City, a Scum blimp will try to fire green lasers at her, which deal a great amount of damage if the rays do make contact with her.
In the credits, Lizzie can be seen standing on the right hand side of George.
In Rampage (2018), Lizzie, who's never referred by this name, is a crocodile who after eating the mutagen canister that fell from the Energyne space station in her Everglades home, is transformed into a massive beast. She eventually comes to Chicago on August 24 1978 after hearing the signal that lured the mutants. She is later killed by George when he impales her in the head leaving her to die and saving Davis.
Lizzie had dark green colored skin with a yellow underbelly, white claws on her fingers and toes and yellow spikes running down from the top of her head down to the tip of her reptilian tail, sharp teeth and a dinosaur-like muzzle. Lizzie has digitigrade legs, much like bipedal theropod dinosaurs. This is the most recognized and iconic image of Lizzie that everybody distinguishes her to be. On the box cover of Rampage: Total Destruction, Lizzie looks much more different to how she looks in-game. She looks much more serious. She also has meaner looking yellow eyes and yellow spikes on her elbows. Her head is also smaller and her teeth are longer.