Mombies are what remains of a number of the numerous soccer moms after the events of Z-Day.
Mombies are former soccer moms who, in order to make some serious impact on the world, attempted to stop Z-Day before it was a well-known fact that the chaos was caused by zombies. Many clutched their children as they died to try and protect them, only to form a prison as the mother's death grip tightened. A number of these Mombies still clutch their still-living children, who scream and plead in sheer terror.
Many Mombies are similar to typical zombies in terms of strategy. However, those who hold still-living children should be attacked on a side that the child is not clutched against if one wishes to attempt to save the child (letting the child perish counts against your "survivors saved" stat and counts toward your "survivors slain" stat).