Do you 'wreak' havoc, or 'wreck' it?

Does one wreak havoc or wreck it? Should one, properly speaking, cry havoc or play it? And before we get into all that, what exactly is havoc? We’re so glad you asked these common, everyday questions.

"Us? Wreak havoc?"

Havoc, in modern use, typically carries such meanings as “wide and general destruction,” or “great confusion and disorder.” 

A 1,300-pound walrus is captivating onlookers while also creating chaos in northern Europe, overtaking and sometimes sinking vessels—all in search of an ideal sunbathing spot! ... With the wily, whiskered animal creating havoc, the country's Directorate of Fisheries is mulling a possible relocation for Freya.
— Anna Lazarus Caplan, People, 28 July 2022

You've also got a little puppy to add to the havoc… Yes, a little girl. Her name's Fendi. She's like my baby.
— Daily Star Sunday (London), 29 Nov. 2020

The Original 'Havoc'

These senses are, it must be said, more lighthearted than the one that the word had when it was introduced into English, when it was essentially an exhortation to engage in plunder and pillage. Havoc came to us, as have many thousands of other words, through the 11th century Norman invasion of Britain. When French-Norman troops were taking an enemy’s stronghold and their commanders yelled “Havoc!” it signaled that the soldiers were free to ransack the city for any objects of value that could be carried off (the word can be traced back to the Old French havot, meaning “plunder”). 

Havoc appears but rarely in print until the 15th century, at which point it is often paired with cry (as in Shakespeare’s famous line from Julius Caesar, "Cry 'Havoc!', and let slip the dogs of war”). Cry havoc has moved into the realm of the figurative since the middle ages, and today is used in the sense “to sound an alarm.”

"Let me point to a certain form of irony: Those who have strong reservation against the European project in general, who would have cried havoc had the European Union ever considered wanting to take up competences in the field of health care, and who would have resisted that with all means, they are now crying havoc that Europe isn’t acting in this field," Timmermans said.
— Politico, 27 Apr. 2020

Of late, Bangladeshi people are having nightmares and crying havoc after watching and hearing the horror news about death of fish, birds, and animals in 'haors' located in areas near India-Bangladesh border.
— The Financial Express (Dhaka, Bangladesh), 24 Apr. 2017

People have not been restricted to crying havoc: one can also play, make, or raise havoc with things, meaning “to do great damage to” or “to throw into disorder and confusion.” These uses are more commonly found in British English; Americans are likelier to use wreak havoc.

'Wreak' vs. 'Wreck'

The verb wreak usually means “bring about, cause” (although it can also mean “to avenge” and “to give free play or course to malevolent feeling”), and this word, rather than wreck, is the one that is most often paired with havoc. There is often confusion about this, and it is not uncommon to find wreck havoc in edited prose, but most usage guides strongly advise to stick with wreak havoc when you wish to say that something causes great damage.

The pandemic and the havoc it wreaked on the supply chain slowed the project, which now is expected to be completed by mid-2023.
— Kathy A. Bolten, The Business Record (Des Moines, Iowa), 3 Aug. 2022

Incidentally, the past tense of the phrase is wreaked havoc, as one might expect, but for much of the 20th century, many people preferred wrought havoc, even though wrought is actually a past tense not of wreak but of work. Happily, English speakers seem largely to have outgrown that habit.

To recap: havoc used to be the signal for victorious troops to begin plundering; havoc can be played, caused, raised, or made; when choosing between wreaking and wrecking havoc you are advised to stick with the former.