A disturbed dandy was captured on video pleasuring himself behind a Spider-Man knapsack while ogling a 24-year-old woman on a Brooklyn subway, cops said.

The Panama hat-wearing, mustachioed creep sat across from the victim at about 10 p.m. April 26 as the northbound R train approached the 53rd Street station in Sunset Park, according to police.

He is seen wearing a fedora, a collarless white shirt, brown jacket, khaki pants and a pair of blue and white saddle shoes.

The anything-but-amazing Spidey fan was described as a white, 5-f00t-9 50-year-old weighing 170 pounds.

Cops are asking anyone with information to call Crime Stoppers at (800) 577-TIPS.