An unhinged creep pleasured himself in front of a 51-year-old MTA token booth operator at a Brooklyn train station, then followed the woman with a knife and threatened to kill her, officials said Thursday.

The MTA employee was working at a booth at the Franklin Ave./Botanic Gardens Subway station in Prospect Heights around 4:45 a.m. Friday when the bandanna-clad perv entered the station and approached the booth. He then exposed himself and began masturbating in front of her, police said.

When the woman’s shift ended and she left the booth, the suspect trailed her to the southbound platform with a knife in his hand, cops were told.

“I’m going to kill you!” the man screamed as he pursued the woman to another token booth, which she jumped in for protection.

She called 911 and took a photo of the man with her phone as he stood outside the booth, cops said. The suspect, in turn, took a photo of the MTA clerk with his phone and fled the train station.

No arrests were made, cops said. The MTA clerk was not harmed.

Police on Thursday released the photo the MTA clerk took of the suspect, hoping that someone recognizes him.

He was described as Black, in his mid-20s, about 5-foot-8 and 170 pounds with brown eyes, blotchy skin and a mustache. He had a long dark afro tied up with a multi-colored bandana and was wearing a black T-shirt and black jeans.

Anyone with information regarding his whereabouts is urged to call NYPD Crime Stoppers at (800) 577-TIPS. All calls will be kept confidential.