The phrase "cry havoc" essentially means to spark chaos or unleash mayhem. It's a powerful and dramatic expression that can be used in various situations. Some synonyms that have a similar connotation include "incite riot," "stir up trouble," "provoke unrest" or "instigate bedlam." These terms all suggest a call to action that could potentially lead to disorder and confusion. Other options include "sound the alarm," "ring the bell," or "raise the banner." While these expressions may not have the same ominous tone, they still indicate a need for attention and action. Regardless of the phrase used, the intent is clear - something big is about to happen.