With CSI in production on its 11th season, creator Anthony Zuiker realized his show needed "event" episodes, he says, "to fight for every eyeball you can." To that end, he's written tonight's chilling installment — his first CSI script since one he wrote in 2006 for CSI: NY.

"I desperately wanted to go back to CSI because I sorely missed it," explains Zuiker, who also launched a popular book series. In 2009, he released Level 26: Dark Origins, featuring lawman Steve Dark hunting down a crazed serial killer named Sqweegel. Described by Zuiker as "a forensics-proof contortionist who wears a head-to-toe latex body condom with eye holes cut out and a zipper across his mouth," Sqweegel appears in tonight's episode and is set loose on Hollywood legend Ann-Margret, cast as a philanthropist with a deep, dark secret.

"This Sqweegel preys upon people who receive accolades and awards for being upstanding citizens, and then snoops around in their homes for months to look for dirty laundry on them," says Zuiker. Unsuspecting Margot (Ann-Margret) becomes his victim when real-life Las Vegas mayor Oscar Goodman hands her the key to the city. According to Zuiker, if Sqweegel discovers dirt on his prey, "He slashes them and says, 'I know. Confess.' If they don't, after a couple weeks he goes back and kills them."

Spoiler alert: Expect Sqweegel to elude the CSI team and cause more mayhem in Zuiker's follow-up novel, Dark Prophecy, conveniently in stores October 14.

CSI airs Thursdays at 9/8c on CBS.

Subscribe to TV Guide Magazine now!