She was portrayed by Marny Eng.
Tabitha was a "normal" human girl in an American farm until her psychic powers manifested and she "scared the horses, hid the remote, did really sick s--t." She was the daughter of the man called "The Architect". She was bullied because of her powers, and her mother had enough of her misbehavior and drowned her in a well.
She returned as ghost and began killing those who watched a video tape of her death in the well. The tape showed "disturbing" images, such as a woman's failed suicide, a lighthouse, and someone taking a dump - from the perspective of the toilet water. Then it showed a corpse-like girl in a room. Whoever watched the tape would get a phone call from Tabitha's ghost saying they had seven days and then they would die in seven days.
Cindy Campbell, a reporter, got news of the stories when crop circles were found on a local farm. Two other women had been killed by Tabitha a week after they'd seen the tape. Cindy realized there was an alien invasion; and thinking the aliens were evil, she decided the tape might hold salvation or answers, and when she watched it, she got a call from Tabitha. Then her son Cody watched the tape and he got a call from the girl. Cindy denied Cody had done this, but Tabitha said "Come on Cindy I do this for a living!" Eventually Tabitha was satisfied into giving Cindy a message (SEVEN DAYS) and left.
The aliens arrived, but after a scene of their attack were revealed to be, in fact, good aliens who had only come to destroy Tabitha and the tape. This issue settled, the humans and aliens began playing golf together. Tabitha hunted Cindy and Cody down into a basement and taunted them, becoming such classic monsters as the Texas Chainsaw killer. But at the climax, Cindy revealed to Tabitha she knew of her trauma, and that what her mother did was bad, and Tabitha was a girl who could belong in her own family. Tabitha pretended to be accepting of this and transformed into her human self saying she was free but then turned back into her ghost form and said "Na bitch I'm just screwin' with ya!" and raised a knife. But then the president of the United States of America opened the door, saying his catchphrase "I want to wish you good luck we're counting on you!" and knocked Tabitha back into the well, where she was trapped again.