A McDonald’s outlet in New Jersey, USA received an unwanted visitor when a man released a giant white rat inside the restaurant.

Customers scrambled for the exit when the man entered the restaurant with a rat in a pet carrier and let it loose on the floor. A video showed that the unidentified man was accompanied by a young boy, and it appeared that he was playing a prank.

CBS Philly reported that McDonald’s was working with the police to identify the person. The restaurant’ operator, Celest Quintana, said in a statement, “The safety of our customers and the cleanliness of our restaurants are our top priorities. Following this incident, our restaurant staff thoroughly cleaned and sanitised the dining area and contacted the police. We are currently working with local law enforcement to identify the person responsible for this deliberate act.

A spokeswoman told NJ.com that the rat exited the restaurant through the front door shortly after the events recorded on the video.