A Pennsylvania man slashed a girl with a razor blade at Dorney Park and Wildwater Kingdom — and bit a man who tried to stop him, police said.

Jorge Otero Jr., 18, was arrested late Saturday at the theme park in Allentown after South Whitehall Township police said he pulled out a razor blade and slashed a 14-year-old girl, leaving a large gash on her left hand, Police Chief Glen Dorney told The Post.

Otero bit a man three times when the good Samaritan tried to stop him from running away, sinking his teeth into the man’s left hand and right shoulder, Dorney said.

“The gentleman actually confronted him and tried to detain him until security got there, but in the process, [Otero] bit the man,” the chief said, leaving the victim with several small cuts and bruising.

Dorney said it’s unclear what led up to the “random, sudden” attack, which occurred during the theme park’s annual “Halloween Haunt” celebration, featuring themed mazes, scare zones and “monsters prowling the park,” according to its website.

“For whatever reason, he decided to do that,” the chief said, adding that the 14-year-old girl knew Otero from school, but told police he said nothing prior to the slashing.

Calls seeking additional comment from park officials were not returned Thursday.

Otero, of Allentown, is facing charges of aggravated assault and simple assault. He was released from custody Sunday after posting $20,000 bail, PennLive.com reports.

Attempts to reach Otero on Thursday were unsuccessful.