The SPAS-12 is semi-automatic and has its stock in the folded position. In "The Defector," the weapon is able to use Dragon's Breath incendiary shotgun shells. The Dragon's Breath is aesthetically identical to the rounds regularly fed into the SPAS-12. The only difference is that the Dragon's Breath has incendiary shells, meaning that the rounds let out fire, symbolizing it's name. The Dragon's Breath also has a wider reticle.
The SPAS-12 is featured in multiplayer. It must be pumped after picking it up and reloading, but operates in semi-automatic mode. It is available for purchase at level 24. The SPAS-12's only attachment is the Suppressor.
It deals medium-high damage, but it excels at close quarters, and is best suited for medium distances, although it will often take two or three shells to get a kill (however at close range more often than not the SPAS-12 will kill in one shot). Contrary to what the stats say, the Suppressor attachment has no negative effect on the SPAS-12.
Although the SPAS-12 has less range and damage per round than the Stakeout, it does have double the magazine size (8 shells, versus 4 in the Stakeout), plus has a much higher rate of fire, meaning that even though the SPAS-12 is less likely to get a one hit kill, it is much more likely to get off a few more follow-up rounds if necessary. However, recoil is high, and unlike the Stakeout there is no Grip attachment to mitigate this. The SPAS-12 is relatively underrated in the online community but can actually be an extremely powerful mid-range and room clearing weapon once the player masters and compensates its rate of fire and range. It can easily out-perform most weapons in close quarters and even at range with an element of surprise.
The SPAS-12 is available in the Mystery Box. It is effective in the early-mid rounds, often capable of one-shot killing zombies, but it has a long reload time as each shell is loaded individually. It is also available as a weapon power-up in Dead Ops Arcade, where it is fully automatic, has increased range, and has a wide spread. This makes it very helpful when fighting large amounts of zombies.
When Pack-a-Punched, the SPAS-12 comes out as the "SPAZ-24" which has a 24 round magazine and when reloading it just takes one shell to fully reload. This version is also fully automatic. It can be very effective at killing masses of zombies in a fast rate making it more helpful when trying to get out of a large crowd. Using Double Tap Root Beer in conjunction with the "SPAZ-24" is a love-it-or-hate it as it can kill large crowds faster, but wastes ammo faster as well. Also 24 is 12 doubled, a reference to the fact that it's damage is doubled.