Waterloo Regional Police have arrested a 27-year-old Kitchener man after responding to an assault on Charles Street East.
Police say the man was found with a rock placed in a sock which was used as a weapon.
Investigators believe the man used a similar weapon in another recent incident involving an assault.
The man has been charged with assault with a weapon and assault causing bodily harm.
A second 22-year-old man was also charged with assault and breach of probation at the scene.
Both men are being held until they appear in court.