Staffordshire Police's Cannock team said in a statement that officers are investigating after the assault on a teenage boy in Cannock Park off Stafford Road, close to the Chase Leisure Centre.
It took place at around 6pm on Friday and six teenagers have since been arrested and bailed.
Police have asked anyone who may have witnessed the attack or have information to get in touch using 101, quoting incident number 669 of February 3.
