The Mark IV tank is a rideable vehicle that appears in the zombies map Origins. The tank is needed to craft the Staff of Lightning, as the player needs to reach high-ground areas that are normally not accessible, in order to acquire staff parts. It can also seen in the intro cutscene alongside "Tank" Dempsey.
The Mark IV Tank can be found under the church near Generator 6 and costs 500 points to activate, by climbing on it and interacting with the control panel. The Tank moves through the muddy road until it gets to the building near Generator 2, labeled "Tank Station", where the engine cools down before it can be used again. Cooling down takes at least two minutes, and takes less time the fewer players stand on it while it is moving. When activated again, it will then continue on the muddy road back to the church, where it will once again have to cool down. The tank can be called from the Tank Station and the church for 500 points from the switch beside where the tank stops, as long as it was once called via the control panel on the Tank.
The Tank itself is very similar to the Bus on TranZit, in ways as such players can utilize the tank as a defensive platform and can move across certain parts of the map. It is possible for zombies to jump onto the tank and attack the players while it is moving, but sometimes the Tank will use the flamethrowers on the sides and fires at nearby zombies to prevent this.
The Tank is required to obtain the Staff of Lightning and thus required for several achievements:
- I'm on a Tank! (10 /Bronze Trophy ) - In Origins, ride the tank around the map without getting off.
- Playing with Power (30 /Bronze Trophy ) - In Origins, build all elemental staffs in one game.
- Master Wizard (40 /Bronze Trophy ) - In Origins, wield all of the ultimate staffs in one game.
- Little Lost Girl (75 /Silver Trophy ) - In Origins, release Samantha.
- When taking the Tank around after the Lightning Staff parts have been obtained, once per round, a random Power-Up will be at each jump-off location. 
- There is one destroyed tank by Generator 5 and another one outside the map which can be seen via no-clipping.