- Extra is only available to Human Team .
- When buying an extra , you will be able to increase your damage done by zombies by pressing [ F1 ] 
- The time at which the damage has been increased - 6 seconds
- How to increase the damage : You get to every part of the body of zombies , and damage increased as if you hit him in the head .

Cvar
-DS Cost [10]
-DS Time [6 second/default]