havoc是不可数名词，常用于短语play havoc with，意思是“对…造成严重破坏，使…陷入混乱”。

The earthquake wreaked havoc on the city.地震对这个城市造成了大破坏。
Continuing strikes are beginning to play havoc with the national economy.持续的罢工开始严重破坏国家经济。
You played havoc with my plan!你搅乱了我的计划！