Blundergat

The Blundergat is a Civil War fever dream — a four-barrelled break-action shotgun, half blunderbuss and half Gatling gun — and the only primary wonder weapon that fires ordinary ballistic ammunition, which means it is the only one Double Tap actually makes stronger. One shot sprays a horizontal line of pellets that fells a whole rank of zombies; then you reload, every single time.

Getting it

On Mob of the Dead it comes from the Mystery Box — or free, by hitting five hidden blue skulls with the Hell’s Retriever, skulls only visible from the Afterlife. The distinction matters: "Pop Goes the Weasel" requires the free one, and a box-bought Blundergat will not advance the quest. Blood of the Dead replays the ritual with the Spectral Shield’s sight standing in for the Afterlife.

Its many upgrades

It was the first wonder weapon with two upgrade paths: the straight Pack-a-Punch into The Sweeper — semi-automatic, double damage — or the buildable Acid Gat Kit into the Acidgat, whose sticky burst-fire rounds pin a zombie in place and then detonate, and which Pack-a-Punches further into Vitriolic Withering. Blood of the Dead added a third road, the fireplace-forged Magmagat, and Black Ops 7’s Paradox Junction a fourth in the Sundergat. Nobody in the fiction ever claims to have built the original; its history, the games admit, is shrouded.