Blundergat

The Blundergat is a new Wonder Weapon featured in the Call of Duty: Black Ops II zombies map Mob of the Dead. It is based on civil war-era weaponry, consisting of ideas from the both the and. Normally, it acts like a single-shot break action shotgun, but when upgraded, it becomes The Sweeper, with a 2 round magazine and 120 ammo in reserve.

When combined with the Acid Gat Kit, it becomes the Acidgat. It has an automatic 3-round magazine. When a zombie is shot while in its upgraded form, they will be stuck with an acid infused round which explodes soon after. When this version Pack-a-Punched, it becomes the Vitrolic Withering. The ammo is expanded to 5 rounds per magazine and attracts zombies before it explodes, similar to the upgraded Crossbow and Monkey bomb.

Trivia

 * This is the first wonder weapon since the Wave Gun that can be Pack-a-Punched, and the first overall in Call of Duty: Black Ops II.
 * It starts to make crawlers at about round 30.