"Commit carnage" is a violent and evocative phrase that connotes destruction and death on a large scale. When searching for synonyms, it's important to consider the nuances of this phrase and the type of violence it implies. Some potential synonyms might include "inflict massacre," "cause bloodshed," "perpetrate slaughter," or "wreak havoc." Each of these phrases carries a slightly different connotation and can be tailored to suit a specific context or tone. Other options might include "unleash mayhem," "cause devastation," or "bring about ruin." Ultimately, the choice of synonym will depend on the writer's intent and the effect they hope to create.