A young college student attends a local renaissance fair where he purchases a sharpened, replica claymore (large, two-handed sword). While waiting for the subway to take home, he decides to practice his swordsmanship. The other waiting passengers step back and watch his clumsy swordplay with amusement. However, one passenger is not paying attention and when the student brings the sword back behind him for a large swing he accidentally decapitates the passenger. Which classification of homicide most closely fits the student's crime?