A rapist dragged a man into bushes in a Staffordshire park before threatening him with a knife and attacking him.
The 27-year-old victim had been followed through Hanley Park and into Shelton Park before he was attacked at about 1230 BST on Tuesday.
The victim reported the rape to a park warden after the attacker had fled.
He described the rapist as eastern European, aged in his 30s, 6ft tall and with short black hair. He wore a black baseball cap with the letters NY on it.
He was also wearing a blue crew-neck T-shirt and black tracksuit bottoms with white stripes down the side.