User blog comment:Damac1214/Black Ops 2 Uprising DLC Trailer Released + Double XP on April 12th to April 15th/@comment-5081943-20130405053653/@comment-173.58.57.123-20130405074319

Probably a Shovel. Or maybe an iron bar, instant death up to round nine, and if the head is hit, a custom animation in the form of grabbing the zombie and smashing their head in, and if another zombie is nearby, the deceased zombie is thrown into the second, killing them both and awarding 260 points plus an additional 100 for the head hit.