A man naked from the waist down kerb-crawled in a blue Ford Focus while following a girl of 14 on Sunday morning.
Police say the incident happened between 10am and 10.30am and are appealing for witnesses who may have seen the car travelling along the wrong side of Pinchbeck Road, Spalding, near to the cemetery.
Det Sgt Lance Morgan said: “This is an unusual but concerning incident that has left a young woman shaken.
“Although the vehicle involved is a common make and colour, the manner of driving would have been very noticeable and I would urge anyone with information to contact us as soon as possible.
Police believe the car may have travelled some distance on the wrong side of the road, including crossing the traffic lights at Woolram Wygate.
The driver, a white male aged 20-30 years, had blue eyes, short brown hair and a scar on his right cheek.
He wore a blue and red striped polo shirt, but was naked from the waist down apart from slippers on his feet.
Witnesses are asked to contact Spalding CID as soon as possible on 101 and asking for extension 2635.
• Information can be given anonymously to Crimestoppers on 0800 555111.