Angela Wesselman, whose real identity is not revealed until the end of the movie, was a troubled housewife who spent the bulk of her days caring for two severely handicapped stepsons and building an elaborate web of online deception until it all spun out of control.
In an exclusive interview with ABC News' "20/20," Wesselman admitted that she's a mastermind of deception.
"A manipulator is what my husband calls me," she said. "But yeah, I manipulate and it's not right. ... I never thought I'd become so entangled in it."
Spoiler alert! All the twists and turns of the movie "Catfish" are revealed in this article.
Wesselman posed as an 8-year-old budding artist named Abby and a 19-year-old teenager named Megan, and lured Nev Schulman, a trusting 24-year-old New York City photographer, into a romantic relationship online.
In the film, Schulman's world comes crashing down when he learns that Megan, the girl of his dreams with whom he's shared the most intimate fantasies, does not exist. Megan and Abby are both characters created by Wesselman's imagination and brought to virtual life on Facebook.
"This woman is exceptional," said Schulman. "I'm totally fine admitting she just outsmarted me."
Wesselman said her problems began when she looked for feedback on her artwork online, and was met with snide and stinging critiques. However, when she posed as an 8-year-old artist named Abby, people online -- namely 24-year-old photographer Nev Schulman -- were kind and accepting.
An online correspondence began and the charade escalated when Wesselman created the character of Abby's older sister.
"I really created [Megan] to make it more of an age appropriate conversation for [Schulman]," she said.
Megan became Schulman's obsession and the core of Wesselman's growing cast of characters. She created online profiles for at least 21 relatives and friends to round out Megan's social circle.
"It's not normal for just one person to be on Facebook ... with just one friend," she said of her logic. "You have to have other friends."
To bring these personas to life, Angela assumed all of their identities. She posted messages on Facebook in the voice of Abby, Megan, their brother and friends, switching minute by minute.
"In my mind there were days where I actually believed that Megan existed," she said. "I immersed myself into thinking that somewhere she's there."
She claimed she had no problem navigating such a complex fantasy world.
"I have been diagnosed as schizophrenic," she said. "But ... I don't think I have multiple personalities in normal life, really. I just think I have the ability to create a lot of illusions for people."
Moviegoers and critics alike have questioned "Catfish's" legitimacy. The New York Times' A.O. Scott scolded the filmmakers for exploiting Wesselman for their documentary -- an accusation which they and Wesselman, deny.
If anyone was led down the primrose path, it was Schulman, Wesselman said.
"When I first started interacting with them on Facebook ... even though I knew it was all a lie ... and all these people were fake ... I was like, 'This would make a great film. ... I hope they're filming it,'" she told "20/20."