A design philosophy in BattleTech gameplay that emphasizes survivability for the BattleMech. A typical Zombie 'Mech can endure a great deal of damage without taking crippling critical hits or losing major weapon systems. Typically such a 'Mech will have heavy armor and limited or no weapons that expose the BattleMech to the risk of (typically fatal) ammunition explosions. XL engines are often seen as a design flaw for a Zombie 'Mech.
In lieu with this philosophy, many variants or modifications to baseline 'Mech models seek to remove ammunition-dependant weaponry.
Note that this is purely a gameplay concept, rooted in the construction and boardgame rules. Within the BattleTech universe the concept is unknown.