Laurie Forman is the sister of Eric Forman and an antagonist from the sitcom, That 70s Show.  She is Red's favorite child. She was portrayed in seasons, 1-3, and 5 by the late Lisa Robin Kelly and portrayed by Christina Moore in season 6.

Laurie Forman

Laurie Forman

She is a college dropout and slacker  once getting a college professor to fall in love with her.  She is a bully to her younger brother and enjoys his misery.  In response, Eric often refers to her as the Devil.

Her crowning moment of villainy came in the second season.  During the season, Michael and Laurie were in a secret relationship, which just consisted of sex.  When Michael wanted to end the relationship as he loved Jackie, Laurie saw Jackie outside and asked Michael for one last kiss.  Michael kissed her which Jackie saw causing their third breakup.  She showed no remorse for this.  During the breakup, Michael and Laurie started dating in the open, though before it was based on mostly sex, but Michael thought there could be more.  However, the relationship ended in the Valentine's day episode when Michael saw a boy leave Laurie's bedroom.  Despite his heart breaking at the fact, it made him realize how he made Jackie feel and asked Jackie not to feel bad for him as he deserves a broken heart. 

Laurie reappeared in season 5 and seemingly redeems herself by telling Eric and Donna to go through their wedding.  In reality, her intention was to make herself Red's favorite again.  At the end of season 5, she marries Fez so he could stay in the country which gave Red a non-fatal heart attack.  During the "marriage," she would have sex with different guys, except Fez.  After season 6 she left the show completely.