Marianna Jekyll

Marianna is a character in the fourteenth Goosebumps Series 2000 book, Jekyll and Heidi.

Jekyll and Heidi
Marianna is the daughter of Dr. Palmer Jekyll and the cousin of Heidi Davidson. When Heidi shows up to live with them after her parents died, Marianna is cold to her, telling her that she needs to leave. Not long after arriving, Heidi finds a room that is torn to shreds, but Marianna claims it was the doing of their cat George, who Uncle Jekyll had to put to sleep for causing so much damage. At dinner, when Uncle Jekyll talks about how the Dr. Jekyll from the story was misunderstood, Marianna gets angry. Heidi soon starts to see things that makes her believe that Uncle Jekyll is a monster. From him coming home late in rough shape, to damage caused in town that is blamed on him. She eventually finds a diary that confirms her suspicions that Uncle Jekyll does know something about a monster. When she sneaks into the lab and sees him ingest a green formula that makes him react monstrously, she believes her suspicions to be true and tries to leave. However, Heidi soon runs into the monster, who tries to attack her. Eventually, Heidi is rescued by Uncle Jekyll as the monster turns back into Marianna. They reveal to her that five years ago, Uncle Jekyll and Marianna had car trouble and were stuck by a forest. When Marianna went off into the woods, she would be attacked by some sort of monster. The result caused Marianna to transform into a monster every night. That's why Uncle Jekyll was testing formulas on himself. Suddenly, the townspeople arrive, intent on killing Marianna and Uncle Jekyll. Heidi and Uncle Jekyll manage to make it out of town, but Heidi escapes with Aaron Friedus and stays with him. However, Heidi soon learns through the diary that Marianna bit her, passing along the curse.

Personality
Marianna is described as being a shy kid when she was five, but at twelve she's a lot more cold to Heidi, as well as angrier to her father, mainly due to having to lie about her monster form and being unable to have friends of her own.

Physical appearance
Marianna is described as being tall and thin with brown eyes and curly black hair, wearing a red and white plaid ski sweater and black leggings.