’You stationed lookouts around my office and you sent this buffoon,’ she nodded at Ron — Malfoy laughed even louder — ’to tell me the poltergeist was wreaking havoc in the Transfiguration department when I knew perfectly well that he was busy smearing ink on the eyepieces of all the school telescopes —Mr Filch having just informed me so.
There are no more uses of "havoc" in the book.
Show samples from other sources
The virus wreaked (caused) havoc in our computer system.
The storm played (caused) havoc with our vacation plans.