Assassinated By: Members of Emilio Barzini's crew
Cause of Death: Machine gun ambush while stopped at a toll booth
Apparently in Mafia films, one bullet to the head doesn't always send a strong enough message. After he's dimed out to a rival family's head by his sister's abusive husband, the Corleone fam's enforcer Sonny (James Caan) gets ambushed by a swarm of hitmen flanking a toll booth.
Not even a 50-pound bulletproof vest could've kept his chest dry from the gunshower he's greeted with; it's almost as if they're trying to spell "Death to Corleones" on his body with slugs, but they keep misspelling words and forgetting to capitalize the "D" and "C" and have to restart multiple times.